Warcraft 3 Image Diskundo.cpp

i just downloaded the 723,458 kb .exe.
i guessed that it was a cd image so I renamed it to .iso and mounted it with daemon
the preview movies work perfectly but when I try to install it, the first file it tries to copy,
the error message comes up:
------------------------------------------------------------------------------------------------------
Setup cannot read a required data file. Your Warcraft III CD may not be in
the CDROM drive. Please ensure that this disc is in the CDROM drive and
press Retry. To cancel the operation, press Cancel.

F:\war3.mpq
Error 0x00000017: Data error (cyclic redundancy check).
(FileUtil.cpp:816)
------------------------------------------------------------------------------------------------------
And when I press cancel:

------------------------------------------------------------------------------------------------------
Setup was unable to copy the following file:
war3.mpq
Error 0x00000017: Data error (cyclic redundancy check).
(C:\temp\02060lockit\Installer\Source\DiskUndo.cpp.240)

Operation aborted.

anybody know how to fix this problem?
I found 80 sources so is this file just messed up by kazaa after being circulated that long (can this happen?)

I tried renaming it to .bin, and I downloaded the cue file, it also mounted fine but same problem
Help would be appreciated, thanks