Try running the game as administrator and repeating, or Download the D2Patch_113d.exe file from here:
http://ftp.blizzard.com/pub/diablo2/patches/PC/ - and run it as administrator. If that doesn't work, I would recommend reinstalling and running that patch file. (As administrator).

Edit: You also should have posted here:
http://forums.d2jsp.org/forum.php?f=34 - This subforum is for site suggestions, not questions.
This post was edited by RaveTheGo on Mar 25 2013 10:32am