A little feedback, please....

Say, I joined GV just a bit ago and uploaded about 5 demos. When I listen to them here they have this bizarro 'fuzz' to them, but only on intro and fade out...I've only heard a few others' here that have a similar sound. Is this me or an upload issue or what?  I'm okay with the demo, yet I'd hate to lose an opportunity due to something I can fix. Would all of you mind having a listen to the demos on my page and provide some feedback.....?
I'm wondering if this happens when converting the file to MP3, although I send them out as 256k...hmmmmm....