Thanks to all of you who tried to help on this one. I found the problem. I had failed to EXCLUDE the file from the build so it was getting wrapped up into the EXE (DUH!) thus it couldn't be edited with the MODI FILE call. The file was being installed separately by installshield but the runtime looked first to the EXE even though the path was being explicitly called. Fancy that! At least I think that's the solution. I solved it by changing the filename and excluding the file from the build.

Thanks again.