Removed invalid formats????

Hi folks,
I am trying to work in an Excel document. I have WIndows XP Pro SP1,
Office2003 SP1. I hit save and a dialog box pops up stating problems were
encountered. There is a marked check box asking to recover the file after
sending the report to MSFT. I hit send and the document recovery window opens
with the file in question and a blank Excel document. The recovered document
is marked as repaired. The indicated repairs state that invalid formats were
removed. I open it and hit save. The error report pops up again and the
process repeats itself. This occurs on multiple machines. I have changed
noted formatting errors inside the document first THEN saving it too. Same
result. Any help at all that can be offere??????????
Thanks!
Matt