You can get an updated DE file for Army Builder here:
http://home.olemiss.edu/~wffurr/darkEldar.40kFixes the point costs for Sybarites and Succubi.
You need to copy this file into the "data" subdirectory of your Army Builder directory, and write over the existing darkEldar.40k file. It'll probably be released in the next datafile update, but here it is in the meantime.
Thanks to Wallace on the AB-40k3 Yahoo group for putting this up for me.
Archon Xanath