kvm is a module for hardware virtualization support. This error just tells that stuff like Intel's VT support is disabled. If you run virtual machines, it'll be slow. If you don't run virtual machines on that box, just disregard this error, as VastOne stated.
Regarding your wifi issues: The rtl8139 driver is an ethernet driver (cable involved). I doubt that this is the chip on your wireless thingie. Feel free to post the output of the command "lspci", so we might find out what chip is on there and which driver you need.