"Type name is invalid" error when executing stored proceedure.

   
When executing the following code.  I get an error "Type name is invalid" #-214?????? on the last line. The command object is executing a stored proceedure on a SQL server 2000 database.  The odd thing is that this code works flawlessly on the development machine but errors on test machines.

    dim LastUpdateStamp as long
    Dim UpdateCheckCmd As New ADODB.Command
    Dim UpdateTbl As New ADODB.Recordset
   
    UpdateCheckCmd.CommandText = "LookForUpdate"
    UpdateCheckCmd.CommandType = adCmdStoredProc
    UpdateCheckCmd.ActiveConnection = NetDB
    UpdateCheckCmd.Parameters.Refresh
    UpdateCheckCmd(1) = LastUpdateStamp
   
    Set UpdateTbl = UpdateCheckCmd.Execute

Are the test machines missing resources? Any ideas would be appreciated

thanks