VB ODBC SQL Is Not Working The Same As MS SQL For Retrieving Data From An ISeries?

I think, although I am not sure, that my problem may stem from the fact that I am trying to do something with a DB2 Packed Decimal Field.If I use MS SQL to import data from an iSeries file I can do something like this Select a, b, c, sum(d) from a file where (criteria here) group by a, b, c Note: field d is a packed decimal field.

In VB using an ODBC connection I can do this: select a, b, c, d from a file where (criteria here)but when I try to do this Select a, b, c, sum(d) from a file where (criteria here) group by a, b, c I am getting an error: -2147467259 (80004005).

I want to do this using VB in Excel because I want the user to be able to input data on the spreadsheet that defines some of the selection criteria.