What did you use to create the ISO? Most likely it did not do a proper job hence the, "Invalid UDF filesystem"..
Try mounting and extracting with Ultra ISO....However, you're best bet is to use the original disc, as suggested, and this time use Imgburn or ultraIso, etc to make your ISO....And check it before returning the original disc..
I read this from an old thread, hope it helps..
"Well this is so old you may have already figured it out, but here goes - I just had the same problem, but found it because I had an iso image that would play just fine on the PC, but when burned to a disk wouldn't play on my DVD player. I got the "invalid UDF filesystem" message when trying to open the image in DVDShrink. So...I opened the image with Ultra ISO and noticed that there was no AUDIO_TS folder, just the VIDEO_TS folder. I added the audio folder, and saved the image with a new name. No more complaints from DVD Shrink, and it now plays on the home dvd player."