Excel 2003 crashes using save as excel 97-excel 2003 & 5.0/95 .xls

I work in a company and GPO has been set in a way so that when a user save his excel work it gets saved in Excel 97-Excel 2003 & 5.0/95 Workbook (*.xls) format. It works for systems having Excel 2000 installed. However, for some reason systems with excel 2003 installed get below error while saving.

Application popup: EXCEL.EXE - Application Error : The exception unknown
software exception (0xc0000409) occurred in the application at location
0x300e2957.

We have tried uninstalling and reinstalling excel 2003 on those specific system but we are not able to get rid of the above error. Is there anyone who can help??

There might be something else that is causing the issue. As far as i am aware, Excel 97 to Excel 2003 uses the same .XLS file format. Only minor changes have been made in Excel 2003 from Excel 2000, i don't think that should affect Excel 2003 in any terms.

I want to know if you are using any Macros?

No we are not using any Macros. I have crossed check each system my self. I can reproduce the error easily, by now i have tried repairing and reinstalling Excel 2003, let me know if there is anything else that i can try out or need to check out.
We don't have any issue in switching those systems to Excel 2003 but i want to know all possible solutions for fixing the mess as we were planning to upgrade all the systems to Excel 2003.

Any further help regrading this will be appreciated.