I'm using vB 2.3.2 and I've installed this hack with no problems whatsoever, however, there was a pretty big problem with the fact that the graphic itself didn't show. It has a nice, big X.
I've went through about ten pages of this thread hoping to grab on to an answer, but I don't think I've passed by anyone that's got quite the same problem I do.
Not only does the graphic not display in the usercp, it doesn't display on a post either (the text is there for the signature, the graphic comes up, again, as an X.)
The <img src=" is returning the following:
signature.php?userid=1&dateline=1061267928
Any clues?
I've reinstalled this thing twice already -- but I'll install it again if that's what it takes.

It looks like a great hack -- hope I can use it soon.
(Could just be it's reeeeal late at night while I'm tryin' to get this on.

)