The orinoco drivers work with Prism chipset cards as well as the original ORiNOCO cards, so the name can be a little misleading.
I haven't used the CVS orinoco driver, but with 13e (the latest released one) you need a patch to use it with Airsnort. http://airsnort.shmoo.com/orinocoinfo.html
The instructions are at the bottom of the linked page.
BTW, I noticed that the page mentions monitor mode being available in the CVS of the orinoco_cs driver but it also notes that Prism headers are unavailable. I suggest you patch and install 0.13e, restart PCMCIA services, do an iwpriv to check for monitor and post any errors you get from Airsnort.