Actually I had the same issue.

Not sure why but I reinstalled Pocket Mac v4.0.20b, but more importantly
I installed PocketMac Driver update -- DriverUpdate.dmg
Driver update to add support for high speed compatible BlackBerry smartphones.
from here:

https://www.blackberry.com/Downloads/browseSoftware.do;jsessionid=AKLX0h5ntI9saO2Ow+60s g**


Haven't had that issue since..hope this helps