make[3]: Entering directory `/usr/src/modules/rt2500'
make[4]: Entering directory `/home/ma3x/linux-2.6.21'
  CC [M]  /usr/src/modules/rt2500/rtmp_main.o
In file included from /usr/src/modules/rt2500/rtmp_main.c:50:
/usr/src/modules/rt2500/rt_config.h:58:40: error: linux/config.h: No such file or directory
/usr/src/modules/rt2500/rtmp_main.c: In function ‘RT2500_open’:
/usr/src/modules/rt2500/rtmp_main.c:272: warning: passing argument 2 of ‘request_irq’ from incompatible pointer type
make[5]: *** [/usr/src/modules/rt2500/rtmp_main.o] Error 1
make[4]: *** [_module_/usr/src/modules/rt2500] Error 2
make[4]: Leaving directory `/home/ma3x/linux-2.6.21'
rt2500.ko failed to build!
make[3]: *** [module] Error 1
make[3]: Leaving directory `/usr/src/modules/rt2500'
make[2]: *** [binary_modules] Error 2
make[2]: Leaving directory `/usr/src/modules/rt2500'
make[1]: *** [kdist_build] Error 2
make[1]: Leaving directory `/usr/src/modules/rt2500'
Module /usr/src/modules/rt2500 failed.
Perhaps /usr/src/modules/rt2500 does not understand --rootcmd?
If you see messages that indicate that it is not
in fact being built as root, please file a bug
against /usr/src/modules/rt2500.
Hit return to Continue