well firstly, i have a hd 6950 and i know it's only using the CPU because it's stuck at a speed of 600Kkeys/sec instead of 20mkeys per sec
Well not to be rude, but are you sure you are using oclvanitygen from the package created by sam7 (
https://bitcointalk.org/index.php?topic=25804)? Make sure it's oclvanitygen (not vanitygen and not oclvanityminer).
And have you made sure to use this format?
$ ./vanitygen -P 041d2e778ae6d9124736df131cd22d3a2483f336c55156d87a84c4bdc6d89f8518e33de85ae0f907a7128c476281bc8cc7742b43a54ccc2c7824dc4c4a438a7fbc 1Boat