Well this is normally due to a corrupt workbook, but if other users can open the file then the file should be OK.
You could try deleting the Excel registry keys in HKLM\Software\Microsoft\Office\9.0 and also in the same place in HKCU. Don't forget to backup the registry before you start doing this though. Also, you could try going to Start->Run and typing in "excel /s" (minus the quotes). This loads Excel in "Safe Mode" - try opening the file now?