It's an issue with Vista (and I think it only applies to GIMP images). (I believe, I've only seen reports of that)
It's a slightly older ASH, but the step2.pl (or whatever it's called) is made to remove the need for tpl slitter.
http://www.filefactory.com/file/af21g2g/n/ASH-Mod_zipBut it is kinda buggy (it was a patchwork job, I don't really know perl... or what the hell I was doing) so you may end up just having to do it manually. (Manual guide in FAQ / ssbbarc in place of manual hexing)