If the post before this one does not work then you will need to start over.
I have no idea if this is the "proper" way to address the issue, but it worked for me. I dealt with this last week.
You should look at the ActiveSync website. You need to pay attention to what version of activeSync you are running. 4.1 was a stable version for the 50v.
http://www.microsoft.com/windowsmobi...c/default.mspx
Uninstall and reinstall. You must turn off all firewalls and antivirus during installation. Turn the software back on after you have established the relationship in ActiveSynch. Make certain they are also turned off on the second computer.
During the setup on the first sync you need to let the computer know you are synching on 2 computers when you see the first dialog box. It has a screen that asks if this you are using this computer as your primary or if you are using 2 computers.
Before you synch the second computer make certain the relationship with the first has been established. You do that by reconnecting and disconnecting several times.
Once you have established the relationships make certain you create a back up using ActiveSync. Do that on both computers. Click on Tools and select Backup/Restore.
Good luck!