I find bluetooth connections with Ubuntu to be a bit unreliable. I have tried it on a number of machines. I have also tried a variety of bluetooth adapters. I'm not sure if it's the various adapters that I've been using. I tried to find a recommended bluetooth manufactor specification, but didn't have luck.
It's not clear what you mean by
adb connect xxx.xxx.xxx.xxx
It's my understanding that you have to specify a port when you use the adb to connect (outside of using a direct connection from the USB).
You can have very reliable transfers and connection using your USB or your wireless. Since you make a reference to adb, I'm sure you already have the Android SDK package installed. So you have access to the adb transfer features (push/pull), using the USB connection.
To use the wireless connection for adb you have to first connect USB then activate the adb tcpip connection to your android. This is done by issuing the following command and specifying the port you want to use. After this activation you can unplug the usb cable and have adb wireless connection that will last until your android is rebooted.
$ adb tcpip 5123
In this example I specified a port that would be unlikely to be a default port for an automatic connection such as an avd.
After you have activated the wireless adb connection for the android you can connect to it by specifying it's IP address and port when issuing your connect command:
$ adb connect 192.168.1.102:5123
I believe your problems connecting adb has to do with your connection setup and parameters.