I'm not very skilled with LUA but it seems this addon hasn't been updated in a long while.
You may be able to eventually get it to work but what if another patch breaks its and still no update?
Besides that the issue can be a lot more then a few lines of code, may want to begin searching for a replacement. Went ahead and googled possible gxCD replacements, found someones forum post, several suggestions on there you might want to try out if you decide to go that route.
http://neriak_x.wowinterface.com/for...ad.php?t=42575