QMO quality.mozilla.org (alpha)

I'm having a problem with FF not loading images from one specific domain. Every other domain I've tried loads images normally, but somehow I've blocked this specific domain. I've asked other users of the domain, but nobody else seems to be having this problem. I can also load images from this domain in other browsers, and I've already checked the hosts file anyway, so it doesn't seem related to that.

I post in many forums but not got the best answer :
http://forums.mozillazine.org/viewtopic.php?f=38&t=981775
gia công nhựa.com/showthread.php?t=123
khuôn nhựa.com/showthread.php?t=114
khuôn mẫu.com/showtopic.php?t=521
đúc nhôm.com/showthread.php?t=1456933
đúc.com/showtopic.php?t=236

I also didn't find anything relevant when I searched for the domain name and IP on the "about:config" page. I also looked at tools > options > content to see if I had any exceptions under "load images automatically", and I didn't.

I just installed FF3, but this problem started before I did that.