I have installed kamikaze, xwrt, webif, batman webif - all ok.
[many webif related questions]
Who wrote the batman webif stuff? Maybe it is a good idea to ask him.
I searched for it and found it at http://x-wrt.googlecode.com/svn/trunk/package/webif-batman The files indicate that the author can be contacted at info@meganetwork.org. But I think it is a better idea to ask at http://forum.x-wrt.org/
And guessing from their script the wl0 must have a ip address to be accepted as interface
Regards, Sven