This may not answer the question you asked, but I had two Real Player AVI videos of half-hour television programs that I was able to join using ImgBurn. I clicked on Write Files/Folders to Disc, then hit Browse, clicked on the first program, then hit Browse again, clicked on the second program, and proceeded as usual to burn the DVD. (Click on the calculator symbol to see how much space is left.) Then I opened my Roxio Disc Copier program, clicked on Browse for Disc Image, found the ISO, and burned the DVD. The two programs joined seamlessly on the DVD.
Strstrk