A lot of wireless nics require a complete reset to come out of monitor mode. This will mean rmmod'ing then modprobe'ing the module. If you are using a PCMCIA card, you may even have to reload the firmware.
tamoneya: What makes you think he is using ndiswrapper? AFAIK ndiswrapper wireless nics always use wlan0 for the interface, besides, if kismet didn't like his card it wouldn't have worked in the first place...