Hy
have a look in ur Quake-directory. If u find there the following 2 exe-files :
"quake2.exe" & "quake2-backup.exe"
than rename "quake2.exe" to f.e. "quake2-old.exe" and rename the "quake2-backup.exe" to "quake2.exe".
Than exec ur Xania-Patch.
I don't know why, but it worked for me :-)