That's just simply the common error... ugh.
I don't know why it happens... as it is not happen on every computers.
Not to mention that it happen on different files... But most common is DWOnline.bin (it's the actual client file)
However, that error tend to be the case by any security program interference during installation, then somehow corrupt files afterward.
You not only have to disable anti-virus program, you will also have to disable firewall, Windows Live Essential, and any other security related stuffs (spyware detector, etc.) and any program that dealing with "scanning."
Always launch program with "Administrator" right.
Check the patch version again, and see if somehow patch skipped or something.
How many times did you reinstalled? If not, you may need to do reinstall and try again?
Some of these patch files have split into 2 parts, so you have to download BOTH Z01 and ZIP one and extract as one single EXE file.
I can't find actual solution as it is different for each time error occurs.
*Beside, if you want to risk it out, save all EXEs in one folder, reboot, launch in Safe Mode and install there... (not recommend if you don't know what is Safe Mode is for...)
Sincerely, Pan2011 ~ Pan2012 (October 11th, 2012)