CRC failed error when extracting files using WinRAR

Hi to all,
I am experiencing some problem while extracting files using WinRAR which I downloaded from the internet. While extracting it shows the following error on my screen:
The error reads as:
Some installation files are corrupt.
Please download a fresh copy and retry the installation
I transferred the same files to my friends computer and extracted them using WinRAR without any error.
Can anyone please explain what might be the problem? I don’t know what to do because every time downloaded data requires to be transferred for extraction, I am met with this error.
Can anyone please help me out in resolving the issue?
I'll be looking forward to your comments.
Regards,
Lopez
