Keep in mind that bgsound is IE only. Also, it must reside inside the head tag. You have it in the body.
Using browser-specific tags is really a bad idea - you're leaving the rest of the world out of your creation. Folks who use oher browsers (there are more of them every day) and find they can't see or hear something just for that reason have a tendency to get touchy. As for me, I go way past 'touchy'.
Firefox says it can't find pmvr.class. As Ruth mentioned, you might want to check their plugins and/or extensions.
In Safari/Mac the menu drops behind the picture. Safari is Mozilla-based, so try adding the following to the top of your _data file...