I'll be the first to admit that I am not a technical guy, but, my wife's camera is 12mp and I can't upload a photo from it to photobucket. My camera is 8mp and I can.
Maybe if you resize your photo so it won't be a large file it might work better.
Sometimes I can't get photobucket to respond with all of those ads running in the background, but most of the time it does work for me with my 8mp camera. I usually start the upload process then do something else for a few minutes while it is processing.