Installing TP-Link TL-WN321G wireless USB adapter on imac g3??

Ok im really new to linux ive used Xubuntu on my really old computer at home thats about it but a few days ago i got my hands on a imac g3 and installed Debian on it im now trying to get the network wireless i have a wired connection but im using my laptop as a router. Everytime i try and make the install the driver for the wireless usb its keep giving me this error:

/lib/modules/2.6.26.2-powerpc/build: no such file or directory. stop

any help would be great..

To build this driver you need kernel sources. You may be able to install it using Debian repositories, did you try that?