Lately i've found PocketMac doing this as well for a few people but works fine for others. I've had two setups, one that works and the other that doesn't sitting next to each other and have gone through all the settings i can think of to find out why, but couldn't. Both have the same laptop and blackberry device.
I gave up in the end and told them to buy Missing Sync for BlackBerry, which so far seems to work with the exception you have to use it's own Notes program for them to sync instead of Stickies on the Mac - which took the guy some time to get used to.