converting Macro's from 2003 to 2007

I have a client that uses a workbook to input data into that will create a fixed width file to import into our software.
The workbook works just fine on office 2003 but when you try to create the flat file in office 2007 the macros place the data in the wrong place. I am stumped at what could be causing the error. I have saved the workbook as macro enabled, I have recreated the workbook in thinking it was corrupt but nothing I do seems to fix the issue. Does anybody have any tricks to get macro's to work in 2007 that were created in 2003?