A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I think the installation files of office have gone corrupt.
Which version of office 2003 are you using?
IF you have disc, try doing an detect & repair or reinstall office 2003.
If no disc, you can try this steps, this might resolve the issue.
Start> run> excel /o > ok
If not follow suggestions below:
Go into Registry Editor (Start, Run, "regedit"). Go to HKEY_LOCAL_MACHINE, Software, Microsoft, Office, 11.0, Delivery. There should be only 1 directory under Delivery, which is your DownloadCode (mine was 90000409-6000-11D3-8CFE-0150048383C9). Select that directory. On the right side of the screen, right-click on CDCache. Change the value to 0.