Please help! I have this annoying error 3 times within 6 months:

-- Calendar
- Some handheld records were not copied to your PC. Your computer may be full or you may have reached the maximum allowed records on the desktop. To correct this situation, delete some records and perform a HotSync operation again.
Desktop = 1165, Handheld = 1144

I am very sure I have lots of free hard disk space in my PC and I have 7MB in my Treo.

What's wrong? anyone can help???????