I've had my share of experiences with non-rolling VWs . . . sometimes they can be a major pain!
First of all are all 4 wheels locked? Just the back? Just the front? Or is just one wheel not turning?
Start with the obvious. If it's just the back, make sure it's out of gear and the e-brake is released. I know this sounds stupid, but I got a pretty nice bug real cheap once because the guy was towing out of his front yard back to his barn and couldn't get the back wheels to roll. He drug it with his tractor, pulled one of the bumper brackets off, bent the bumper and tore up a fender. When I was getting ready to winch it onto a trailer, I dropped the e-brake handle and it started rolling back down the hill it was parked on!
If it's all four wheels, pump the brake pedal. If it's rock hard, or not coming back up, you may have pressure on the hydraulic system. Open the bleeder screws and see if it releases pressure. When a flexible hose starts to go bad it can act like a check valve and let fluid in, but not let it back out . . . but it usually does this one wheel at a time . . . opening a bleeder screw should free it up so it will roll if that's the problem.
Those are the easy ones to fix. About all that's left is the shoes have rusted to the drums. Jack it up and pull one wheel at a time . . . get the biggest hammer you can find and give the face of the drum a good whack and see if the shoes will turn loose. If you can find a 5 or 6 foot section of heavy gauge angle iron, drill it so you can bolt it on with two adjacent lug bolts. Bolt it on and have someone bounce on it while you strike the face of the brake drum. It might help to heat the drum with a torch if nothing else works.
