Personally I'd get the dremel out and cut or drill the head of the screw off, then use a pair of pliers on what remains when the bracket is out. You could otherwise try filing the head so that it could be gripped with pliers.

Whichever you choose to do, I'd recommend masking off the player with tape and aluminium foil to prevent metal particles getting into it. (Aluminium wont give you any static problems like plastic might)