Cannot establish ActiveSync connection via Bluetooth
Device cannot connect to computer using Bluetooth ActiveSync. “Serial port” (instead of “ActiveSync”) is showing as the only service offered by the computer.
1. Delete the Bluetooth pairing from the device and computer
2. Pair again by using the device to add the computer as a Bluetooth device.
3. In the device registry, delete all the keys below HKLMSoftwareMicrosoftBluetoothActiveSync, don’t delete the key “ActiveSync” itself and the DWORD values “BatteryPrompt” and “Initialized”, and the binary value “LastConnected”. There should be one or more keys with a 12 hexadecimal characters name, delete all of them.
Reference:
http://www.geekzone.co.nz/forums.asp?ForumId=6&TopicId=16482