PhpED works is 32-bit only but works fine on 64-bit Windows (as do most 32-bit apps).
CRC errors during installation would often indicate a corrupt installer. Most installers checksum their contents to ensure they are intact.
If the CRC error is from Windows then it might indicate disk corruptions. Viewing the Windows system event log would probably confirm that.
If the CRC error is from PhpED itself, then it might indicate a software corruption such as what a virus might cause. However, not many applications do CRC checks on themselves and I don't think PhpED does.
Remember that if you want a response from NuSphere then you should report issues to direct to NuSphere Support
http://www.nusphere.com/contact_us/