Hey man, I had the same exact issue, and it took many hours to get it to work right. Are you doing this on a Mac? Just wondering as I thought this might have been the reason I couldn't get it to work.
Anyways, I tried many different things (i.e. installing VZAccess Manager and removing it, installing BlackBerry Desktop software, removing it, etc.) but I think what finally got it to work was installing the updated modem drivers from BlackBerry's website.
Go to BlackBerry - PDA Software Downloads - Support & Services at BlackBerry.com
and select "Download BlackBerry Device and Desktop Software" and then select "BlackBerry Desktop Software 4.3". Go down to the bottom and download "BlackBerry USB and Modem Drivers (English)". After I installed those and then reinstalled the VZAccess Manager software I had no issues.