the configure command doesn't work
the make command says cannot find the source files in /lib/module/build
please specify with the KSRC=path
i cannot find the correct path
Ok first, you will need the Kernel source of your current kernel (or at least the Kernel header) to get this compiled .
Usually "/lib/modules/<Kernel-Version>/build" is a link to your kernel, for example i use the kernel version 18.104.22.168
my "/lib/modules/22.214.171.124/build" points to "/usr/src/linux-126.96.36.199".
I think it will be better when you use the driver source from http://rt2400.sourceforge.net.
Here are some link's which will help you.
(HOWTO's for different distros)
The whole magic is the link to the Kernel source, if this is fulfilled the compilation, installation is equal
# make install
if you are Debian( testing ) user you can do a
# apt-get install rt2500-base rt2500-source kernel-headers-<your-kernel-version> module-assistant
# module-assistant prepare
# module-assistant get rt2500
# module-assistant build rt2500
# dpkg -i /usr/src/rt2500-<your-kernel-version>_i386.deb
I hope this can help you a bit.