sql server 2005

it says what the problem is: "Arithmetic overflow error converting expression to data type tinyint."

in your sp, you are trying to cast/convert/assign a big integer to tinyint... post the code, or find the varieble which is defined as tinyint and make it int or bigint

I believe its 2008

http://support.microsoft.com/kb/961695

i'm using sql server 2005.

And the code is in this block:

                  UPDATE  BsYr SET PlnUpdated = 1,
                        PlnIP = PlnIP/(CASE [cntContr]
                        WHEN 1 THEN ((Mn1 - 1) + ((13 - Mn1) * (1 + Mn1IP)))
                        WHEN 2 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1IP)) + ((13 - Mn2) * (1 + Mn2IP)))
                        WHEN 3 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1IP)) + ((Mn3 - Mn2) * (1 + Mn2IP) * (1 + Mn1IP)) +
                        ((13 - Mn3) * (1 + Mn3IP) * (1 + Mn2IP) * (1 + Mn1IP))) END),  
                        PlnOP = PlnOP/(CASE [cntContr]
                        WHEN 1 THEN ((Mn1 - 1) + ((13 - Mn1) * (1 + Mn1OP)))
                        WHEN 2 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1OP)) + ((13 - Mn2) * (1 + Mn2OP)))
                        WHEN 3 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1OP)) + ((Mn3 - Mn2) * (1 + Mn2OP) * (1 + Mn1OP)) +
                        ((13 - Mn3) * (1 + Mn3OP) * (1 + Mn2OP) * (1 + Mn1OP))) END),  
                        PlnTot = PlnTot/(CASE [cntContr]
                        WHEN 1 THEN ((Mn1 - 1) + ((13 - Mn1) * (1 + Mn1Tot)))
                        WHEN 2 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1Tot)) + ((13 - Mn2) * (1 + Mn2Tot)))
                        WHEN 3 THEN ((Mn1 - 1) + ((Mn2 - Mn1) * (1 + Mn1Tot)) + ((Mn3 - Mn2) * (1 + Mn2Tot) * (1 + Mn1Tot)) +
                        ((13 - Mn3) * (1 + Mn3Tot) * (1 + Mn2Tot) * (1 + Mn1Tot))) END)  
                  FROM TRP.FFS_Data_ProjBase BsYr INNER JOIN TRP.FFS_Data_ProjBase_Calc calc ON
                        BsYr.Parent_Id_sfx = calc.ParentTIN AND
                        BsYr.FFS_Contract = calc.TypeOfContract

So, check the datatypes of the various columns involve and set up a SELECT statement that will "select" the values you are trying to update the tinyint columns too.  When you execute the SELECT statement, it should show you which of the tinyint columns you are overflowing.

UPDATE  BsYr SET PlnUpdated = 1
FROM TRP.FFS_Data_ProjBase BsYr INNER JOIN TRP.FFS_Data_ProjBase_Calc calc ON
                        BsYr.Parent_Id_sfx = calc.ParentTIN AND
                        BsYr.FFS_Contract = calc.TypeOfContract

This one alone run fine. And in this table only PlnUpdated has tinyint and the rest of the columns (PlnIP, PlnOP, PlnTot) has float.