# modprobe cxacru
If that produces no errors then the module has been loaded. However, this page http://accessrunner.sourceforge.net/driver.shtml
says that it currently isn't included, in which case you'll need to grab the appropriate driver, etc. and recompile the kermel.
(It might just be easier to get a router - that way you won't have to deal with any of this hassle, and will also be able the connection between multiple machines easily)