I have noticed something, due to RCMerchant's post and cry of frustration here:http://www.badmovies.org/forum/index.php/topic,112594.msg127208.html#msg127208
If I look at that post with Firefox 2.0, I can see his attachment fine. If I look at it with IE 6.0Sp2, I cannot. My guess is that this is being caused by a bug in SMF. Anyway, I can see the correct source code under Firefox, but not IE. That means either SMF is not serving it correctly to IE, which some quick checking appears to be the issue, or that IE drops the attachment coding for some reason.
One of my intents this weekend is to get the default SMF theme changed so that it follows the normal forum color scheme. Maybe that will fix this issue. One of the reason I want to go to the default theme is to avoid the issues you run into using a custom one (I have fixed several already). The Helios looks nice, but I would prefer to go for the best functionality.