Hello Gentlemen

I am a little stumped on something and I hope you guys can help

We have a website we use for a front end to a bitcoin mining pool

the address is www.bitminersunion.org

well the button on the login form

is green in firefox
shows up as a broken image in internet explorer
and looks strange in safari

i cant figure out why
could someone look at our source and maybe give me a hint or two as to how i can fix this ? We would be GREATLY APPRECIATIVE!