It ought to work. Can you be more specific about the problem? When you turn the headphones on and your A100's Bluetooth on, does the A100 even see the headphones? You can tell by going to Settings->Bluetooth, and seeing if the headphones are detected. If not detected, then see if the headphones can pair with something else, like your cellphone. If not, there's a problem with the headphones.
If the A100 can see the headphones, then make sure you're entering the corrrect passcode--the headphone manual should tell you what the default passcode is.