Well, first of all, update your linux aironet driver.
Go to sourceforge.net and search for linux aironet and you will find the new drivers that support rfmon mode. Then recompile either your kernel with the new driver or better...disable pcmcia in the kernel and install pcmcia as non kernel integrated. Then come to http://www.remote-exploit.org get your wellenreiter and you got a program that works fine with ciscos, i develop most part of the code for one :-) Greetings

Max