Leftview in splitterwnd disappears under '95

Hi - I have a fairly large piece of software, and it works fine under the IDE, and even the release build works perfectly, no memory leaks or anything - so half an hour before the demo needed to be shipped I build an Installshield for it and ****, wouldn cha knowit. The whole left pane is missing, invisible, rendering the thing completely useless. I reckon I'll be here looking for work next week. I built it in a few different configs, but to no avail, although it does work on NT Server. 95 & 98 are right out though. Anyone come accross something like this before? Any help would be much appreciated, because the project is huge already. Anyway, I'll be sitting here building every version I kept since January and testing them....need...sleeep.....
hav@XXXsoccermailXXX.com