That error is generally an indication of a low memory condition, forcing a disconnect of your synchronization [or other file transfer] session.
Check to see that you have sufficient RAM available on your Palm device. Consider moving applications and support files to an SD expansion card, using a utility like PowerRUN, if you do not have sufficient free memory.
http://simple-palm.com/index-e.html
If that is not the problem, check to be sure that Verizon's Wireless Sync application on board your device is set to allow the use of other synchronization software. If that option is set properly, consider performing a hard reset of your Treo to correct the problem.
This issue has nothing at all to do with the Missing Sync for Palm OS, with iSync or with the Palm Desktop. It's all about your device configuration.