I have a similar problem. I have the blackbery 9780 and an apple desktop. It used to syn my calandar both from my BB to my ical on my desktop, and also from my ical to the BB
Now it is not syncing at all, even though the Blackberry Desktop Software says it sync'd

What do I do??

Do u activated the iCloud? If yes, then is this the problem because you dont have any entries localy. All Informations are saved in the cloud. You should make a local copy.