esiu, welcome, I have not seen this error before. It is occurring when nLite is scanning your source. You say the source is XP Pro x64 but the message says XP x64 2003. Sounds like Server 2003 64 bit to me - nLite should work OK. How did you copy the source CD? What machine are you running on (Windows version?) Please look in your System Log for CDPROM bad block messages. Try using nLite to do the copy - just browse to the CD. I had a copy problem once but it did not cause nLite to fail, but the install gave all kinds of strange errors. I cleaned the CD and copied again (getting no errors in System Log). Enjoy, John. John, Thanks for your reply. The CD is XP Pro x64, not sure why nLite says 2003 (2003 edition?). I tried both reading directly from the CD and copying to hard drive first. When I use the CD the error shows up after the files are copied - although in the copied directory there is one file missing: AMD64\LANG\MSMINCHO.TT_ but if I copy the files myself I get the error almost immediatelly when it says "Scanning". I tried on 2 different machines, both running XP Pro x86. Any ideas?