error: cannot open display: 0 when trying to launch Firefox
 

So I just installed 32-bit Squeeze. I've done exactly two things since booting into the first install: apt-get install gtk+2.0, and ./firefox, so unless gtk did something, this might be an easily fixable problem with Debian itself. After installing gtk and trying to run firefox via command line, it tells me
I googled a bit and couldn't come up with a solid solution, but the problem seems to be around other places. Any idea how to fix this?

I guess you're trying to run firefox an a different user, than the one that is logged in X

ah okay I feel like an idiot now.
I was still in root from installing gtk. changing back to my regular username fixed it. Thanks lol