I've just rolled my own 2.6.14-archck1 kernel, and the rebuild of my wlan-ng wifi driver failed against it. iphitus is sure that this not related to archck. It is therefore a general incompatibility between wlan-ng and the 2.6.14 kernel, and I have posted it on the relevant mailing list.
Whenever I get an update, I'll post it here.
I've now checked out the current version from svn, and it's working fine. I have a PKGBUILD for this if anyone wants it.