One of the parts is corrupted. You may need to redownload that specific part. If the archive included .rev (recovery) files, you can use WinRAR to repair the set.
When a file is very large (like a high-definition movie, a software suite, or a game), it is often split into smaller "parts" to make uploading and downloading easier. 98c1004c852b489bad8cee503f5e545c.part01.rar
Because the filename is obfuscated (a random string of letters and numbers), it is impossible to verify the contents just by looking at it. One of the parts is corrupted