I have seen corrupt contacts do this before or calendar entries.
you can try this to rectify
Start with this.
KB10953 - Contacts do not synchronize between BlackBerry smartphones and Microsoft Outlook
Also this works well too
In outlook Make a new folder for contacts called backup
move all contacts to the folder and wait for all to be removed from device
then pull battery on device and put back in
After device boots move contacts from backup to the contacts folder and wait for them all to appear
Make a new contact in outlook and see if it gets to the device.
Backup device then in Outlook
highlight calendar
goto file import/export
choose export to file
choose Persoanl folder pst, next
make sure calendar is highlighted and choose subfolders if you have them, next
save to desktop with a name you can remember, Finish
Click ok on screen popup
Go to view, arange by events
delete all entries.
KB04950 - How to reset the BlackBerry smartphone calendar application
close outlook and any word files, open outlook back up after 15 seconds.
Then
goto file import/export
import from another program or file, next
choose Persoanl folder pst, next
find the file and import
Choose highlight calendar and Finish
Change view back to what you want and try again.
