Wii game downloads not able to extract... believe the file is corrupt

Ratatouille (U) & Puzzle Kingdom.... both didn't work. :(

ok 3 questions to diagnose the problem.
A.is the file size you are trying to extract the same as the file size on the download page?
B.is your extracting program up to date(rarely it is this problem.)?
C.are you downloading from a manager or google CHROME cause when you download from these, sometimes they place the file PREMATURELY on the download folder when it is not done downloading?

Replying to #2

Actually it's quite a common issue, a lot of our files are now packed with the rar5 algorithm, which requires a version of winrar above 5.0 to open, otherwise it will say the file is corrupt

Try again with latest WINRAR v.5.0 or newer.

or you could try with the 7-zip. I have ever unzipped a file with 7-zip, which I couldn't do with WinRAR. CMIIW.

7-zip cannot open rar5 files to my knowledge.

7zip does not support rar5 for older version(including the current stable one), but 7-zip still being updated.

Why can't 7-Zip open some RAR archives?
7-Zip still doesn't support new RAR 5 format. 7-Zip supports RAR 2/3/4 formats only.

here is something from their faq pages. so till new update says otherwise, thats the facts at the moment.