I ran into this issue and found the following information on Microsoft's site that resolved it.
Microsoft Office 2003
To resolve this problem in Microsoft Office 2003, follow these steps. 1. Click Start, point to Settings, click Control Panel, and then double-click Add/Remove Programs.
2. Click Microsoft Office for 2003, and then click Change.
3. Click Add/Remove Features, and then click Next.
4. Click Choose advanced customization of applications, and then click Next.
5. Click the plus sign (+) next to Microsoft Office Access.
6. Click the arrow next to Calendar Control, and then click Not Available on the menu that appears.
7. Click Update.
8. Repeat steps 1 through 4.
9. Click the arrow next to Calendar Control, and then click Run from my Computer on the menu that appears.
10. Click Update.
Regards,
Chris