troubleshooting a difference between: install, image, restore v InstDMG deploy (Snow Leopard)

I have had a very easy time so far making a Snow Leopard image build with InstaDMG and deployment via DeployStudio (yes all built in SL too). But I've suddenly hit a very specific but dealbreaking snag. When I try to install Extensis Universal Type Client 2.1 - the most recent version specifically built for snow leopard - i get a dud install on a mac imaged from the instadmg-rolled DMG. BUT if i do a vanilla install of SL on a client and use DStudio to make an image and restore that image to a mac, installing UTC2.1 works fine. For ages I thought this was a problem with UTC2.1 - no other applications were giving me problems - but then the fresh install from the DVD worked ok. Then I stripped back the InstaDMG build chain to JUST the base OS dvd DMG (made from the same installer DVD) and the two small createuser and clearreg PKGs, and that gives me a non-working app. To summarise: I have 2 systems - one from a vanilla install from the SL DVD (then made into an ASR image and re-restored to another mac), and another made by making a DMG of the same DVD, running it through InstaDMG with a an absolute basic build chain and restoring the result to a disk by ASR. Somehow installing UTC2.1 mpkg installer gives me different results on the two resulting systems. On the InstaDMG route UTC shows "Font unobtainable" in the previews and you can't activate it (but you can 'collect' the font to the desktop and pop that file in ~/Library/Fonts!) So first off, what I am asking very generically is, has anyone got any tips on how to troubleshoot where the difference may lie? Second, more specifically but less likely, if anyone else is working on the same sort of build: SL + InstaDMG + UTC2.1, do you have the same issue, or, more hopefully, have you had no problem at all, and I'm the big doofus somewhere in all this. [this is a bit tl;dr, but thanks for any help given]