Using Local variable Nvarchar(max)

I created  a routine to dynamically create tables in my current database from the structure found in another database.  I originally created it on my local machine and it works perfectly.  Then I went to a customer's machine who is also using SQL Server 2008, but only has 4 gigs in memory, and had problems.  

when I set the local variable  to nvarchar(max)  or nvarchar(4000)
The create statement is truncated

When I set the local variable to nvarchar(2000)
the statement creates properly for selected tables that do not have many columns

Why is this happening?  

Second question:  I also moved this procedure to a machine that has sql 2005 installed and I ran the proc to see what problems I would get.  The code works fine for all tables except two where the table structure is longer than 4000 bytes.  
Is there a way to get around this problem?  
I tried showing the len(@vsSQL) and for tables that created properly some of the lengths were over 4000 bytes and for the two tables that have problems, the length is over 4000, but not as long as a few tables that created properly.  Obviously, I can't depend on this count.  
Here is the code:
   declare @vsSQL nvarchar(max)
      declare @execsql nvarchar(max)
      declare @vsInsertSQL nvarchar(max)
      declare @vsTableName varchar(50)
      declare @cprdbName varchar(100), @dbName varchar(100)
      declare @serverName varchar(100), @primComp int

      set @primComp = (Select PrimaryComp from InitialSetup)

      set @dbName = (Select DatabaseName from Specifics where SiteNO = @primComp)
      --  Step 1 set database to bulk logged
      Select @execsql = 'Alter Database ' + @dbName + '  Set recovery Bulk_Logged;' + CHAR(10)
      --Print @execSQL
      execute sp_executesql @execSQL
      

      --  Step 2 determine location of the Production server name
      set @cprdbName = (Select ProductionCPRLocation from Specifics where SiteNO = @primComp)
      set @serverName = (Select ProductionServerName from Specifics where SiteNO = @primComp)
      --  Step 3 if the linked server name does not exist, add it using dynamic name
      Select @execsql = 'if  not exists(Select srvname from master.dbo.sysservers where srvname = ''' + @serverName + ''')' + CHAR(10) +
                  'begin       exec sp_addlinkedserver @server=''' + @serverName + '''  end'
      --Print @execSQL
      execute sp_executesql @execSQL

      -- Step 4 Create Synonyms for objects int the production database name
      Select @execsql = 'Create synonym dbObjects for [' + @serverName + '].' + @cprdbName + '.sys.objects'
       --Print @execSQL
      execute sp_executesql @execSQL
      Select @execsql = 'Create synonym dbColumns for [' + @serverName + '].' + @cprdbName + '.sys.Columns'
      --Print @execSQL
      execute sp_executesql @execSQL
      Select @execsql = 'Create synonym dbType for [' + @serverName + '].' + @cprdbName + '.sys.Types'
      --Print @execSQL
      execute sp_executesql @execSQL
      Select @execsql = 'Create synonym dbIndexes for [' + @serverName + '].' + @cprdbName + '.sys.indexes'
      --Print @execSQL
      execute sp_executesql @execSQL
      Select @execsql = 'Create synonym dbIndexCol for [' + @serverName + '].' + @cprdbName + '.sys.index_columns'
      --Print @execSQL
      execute sp_executesql @execSQL

----------------------------------------------------------------------------------------------------------------

      -- Step 6 generate Create table statements from production database
      Declare TCursor2 Cursor for Select TableName from CopyTables
      Open TCursor2
      Fetch TCursor2 into @vsTableName
      while @@FETCH_STATUS = 0
      begin
            
        --  Step 2 generate Create table statements from CPR7 database
        
        select @vsSQL = 'CREATE TABLE ' + @vsTableName +  ' ('
      
            select @vsSQL = @vsSQL +  sc.Name + ' ' +
            st.Name +
             case when st.Name in ('varchar','nvarchar','char','nchar') then '(' + cast(sc.max_length as varchar) + ') '
                    when st.name in ('numeric', 'decimal') then  '(' + CAST(sc.precision as varchar) + ',' + CAST(sc.scale as varchar) + ') '
                    else ' ' end
                    +
            case when sc.is_nullable = 1 then 'NULL' else 'NOT NULL' end + ','
            from dbObjects so
            join dbColumns sc on sc.object_id = so.object_id
            join dbType st on st.user_type_id = sc.user_type_id
             
            where so.name = @vsTableName
            order by  sc.column_id
             
             --    add Primary key constraint
             Select   @vsSQL = @vsSQL + 'Constraint [' + si.name + '2'  + '] PRIMARY KEY CLUSTERED ( '
             from dbObjects so
             join dbIndexes si
             on so.object_id = si.object_id and si.type_desc = 'CLUSTERED'
             where so.name = @vsTableName
             
            --  add Primary key columns
            Select   @vsSQL = @vsSQL + sc.name + case when sic.is_descending_key = 0 then ' ASC,  ' else ' DESC,  '  end
            from dbObjects so
             join dbIndexes si
             on so.object_id = si.object_id  and si.type_desc = 'CLUSTERED'
             join dbColumns sc
             on sc.object_id = so.object_id
             join dbIndexCol sic
             on sc.object_id = sic.object_id and sc.column_id = index_column_id and si.index_id = sic.index_id
             where so.name = @vsTableName
             order by key_ordinal



            select @execSQL = substring(@vsSQL,1,len(@vsSQL) - 1)  + '))'  
            Select @vsInsertSQL = Len(@vsSQL)
            Print @vsInsertSQL
            Print @execSQL
        
        execute sp_executesql @execSQL
          
        fetch next from TCursor2 into  @vsTableName  
      end
      Close TCursor2
      Deallocate TCursor2


------------------------------------------------------------------------------------------
      -- Step 7 Insert all rows from Productions version into cPR_Reporting

      Declare TCursor3 Cursor for Select TableName from CopyTables where tablename not in ('LineItemLinks', 'LineItemsAssigned')
      Open TCursor3
      Fetch TCursor3 into @vsTableName
      while @@FETCH_STATUS = 0
      begin
        -- Step 3 Insert all rows from Productions version into cPR_Reporting
            select @vsInsertSQL = 'INSERT INTO ' + @vsTableName  + ' (' + char(10)
      
            select @vsInsertSQL = @vsInsertSQL + ' ' + sc.Name + ','
             from dbObjects so
             join dbColumns sc on sc.object_id = so.object_id
             join dbType st on st.user_type_id = sc.user_type_id
             where so.name = @vsTableName
             order by
             sc.column_id

            select @vsInsertSQL = substring(@vsInsertSQL,1,len(@vsInsertSQL) - 1)  + ')' + char(10) + 'Select '
            select @vsInsertSQL = @vsInsertSQL + ' ' + sc.Name + ','
             from dbObjects so
             join dbColumns sc on sc.object_id = so.object_id
             join dbType st on st.user_type_id = sc.user_type_id
             where so.name = @vsTableName
             order by
             sc.column_id
             
             
             select @execSQL = substring(@vsInsertSQL,1,len(@vsInsertSQL) - 1) + char(10) + 'from [' +
                    @ServerName + '].' + @cprdbName + '.dbo.' + @vsTableName + CHAR(10)
             Print @execSQL
             execute sp_executesql @execSQL
        
        fetch next from TCursor3 into  @vsTableName  
      end
      Close TCursor3
      Deallocate TCursor3

      -- Step 8 drop synonyms
      DROP SYNONYM dbObjects
      Drop Synonym dbColumns
      Drop synonym dbType
      Drop synonym dbIndexes
      Drop synonym dbIndexCol
      
      -- Step 9 Alter database
      Select @execsql = 'Alter Database ' + @dbName + '  Set recovery simple;' + CHAR(10)
      -- Print @execSQL
      execute sp_executesql @execSQL


Any thoughts would be greatly appreciated.