Hi SteveE,
If you are looking for the NJVC ISOs, this is the wrong thread. Go here instead.
If you are having trouble with ROTJ 2.5, it isn’t in ISO form. There are MKV, AVCHD, and NTSC DVD5 versions.
In that case, you need to follow this guide for the procedure and go to this guide for the relevant links. It won’t be as fast as using torrents, but the file integrity will be much more reliable.
Can’t help with the Demonoid issue.