CRC is also known as a checksum. The archive has an expected checksum value stored in the file and the RAR decompresser calculates the value from the complete file. If the two values are not identical you get the above error. What that means is that something went wrong during the transfer and at least one of your rar files is defective and needs to be downloaded again.
I would look again at your router.Installing the Windows Installer update may also help. The Windows Installer update can be downloaded from Microsoft's Website Micro inst You might also want to check that NetBIOS has access to the internet.