507 = no software on the handheld. Congratulations.
Download the latest software from the Alltel web site. Execute the download program.
Locate and delete "Vendor.XML" on the C: drive of your PC.
Start Desktop Manager. Applications Loader should reload the OS.
I think NJ is a TMo or Cingular subscriber, Alltel may be week in the BB support are as their one of the newer carriers deploying BB's to clients. No excuse but could be a leaning curve on their support end... Follow NJ's instructions for the 507 error and you should up and running ion no time.