windows vista / windows 7 UAC, mentitioned like 100 times on this forum ...
you installed EQ on C: and UAC prevented the files from beeing updated / overwritten ...
try this
http://moestaverne.com/eqemulauncher122.zip just extract it anywhere (EQ directory would probably best) start it, set the path to EQ and it will patch the files automaticly ...
or disable UAC ... or delete the files in the folder first, then extract and overwrite ...