Let’s take it step by step.

First, are you using the official uloz.to links provided in the guide at the link below?:

If so, what method are you using to download them?

Do you know how to compare checksums? I have SHA-1 checksums of those rars when they are confirmed working. I can send you that info via PM if it would be useful.

If all else fails, I have alternative mega.nz links to any of the parts to the ROTJ 2.5 MKV that I can also PM you if you like.

(Edit: Posted before I saw Bluto’s response)