Which download did you try? The one direct from the website named: "pioneer-20140315-win32.7z"?

Also as Walterar asked are you using 7-zip? It's a free program and very popular these days.

i have winrar and this has only happened to me lateley

and yes i have been playing since last year and have tied many times

Ok well can I suggest that you try using 7-zip since it is compressed using 7-zip and someone might have accidentally changed the settings to something that WinRAR cannot decompress. 7-zip is free this won't cost anything.

Also what was the version you downloaded? It might have just been that one that was corrupt, or have you tried several versions?

They decompress just fine for me and no-one has mentioned having a problem.

i have tried several and have tried it on 7-zip too

PROBLEM SOLVED firefox was making it corrupt so i have to use chrome now

For some reason the exe file wont start it says "This application has requested the runtime to terminate it in an unusual way" 

For the record:

I had the exact same sort of problem for quite some time - usually took multiple retries to download uncorrupted file.

I don't know what it was for sure, but it went away coinciding with me moving my USB wi-fi adapter to the front of my rig where it no longer overheats.