V00D00, I looked at the source for the page you sent me and found this for the one that didn't show:
And this for the one that did show:
As you can see, it is leaving a blank line in the HTML instead of putting the appropriate line in. Have you tried clearing the cache, rebuilding stat files and all that jazz to see if it is something random or something that happens to the same post everytime? Also, is there any pattern, like it always happening to the same person or anything like that? Do you have megamods installed?
Raichu, do you mean you think it is when the server is low on memory, or the client? The client being low on memory really shouldn't affect this I wouldn't think. Do you have megamods installed?
ZoneX, did you remove megamods and the problem went away?
DBZFanCentral, I suspect you missed something in the code, but I've been away from this hack for so long that I can't say exactly where to look off the top of my head

Email me the files that are edited by the hack and I'll look over them and make sure they all look right.