It sounds like with the wired version, you are not having any problems - so either your rootooth is defective, or there is something that is causing it to have problems.
You might be having issues with other devices potentially connecting to your rootooth and taking precedence over your computer. So say if you connect to the rootooth with your computer, and then later on connect to it with your phone (when your computer is off), and then try at a later date to connect to it with your computer again (with your phone on, but say in your pocket) - you might not be able to connect to it with your computer.
More likely, your rootooth might just be setup wrong (wrong baud rate or something). I would highly recommend taking a look at this tutorial because its should go over the exact problems that you are having issues with: