Sorry, the original post is mine, since "Marco Peddis" is a shared account. Now I have my own account.
Back to topic, the error log is here I hope it's meaningful too:
make -C /lib/modules/3.6.6/build SUBDIRS="/usr/src/promethean/kernel" modules
make[1]: Entering directory `/usr/src/linux-headers-3.6.6'
CC [M] /usr/src/promethean/kernel/Mathrout.o
In file included from /usr/src/promethean/kernel/Mathrout.c:6:0:
/usr/src/promethean/kernel/usbpromethean.h:37:6: warning: conflicting types for built-in function 'round' [enable$
CC [M] /usr/src/promethean/kernel/usbpromethean.o
In file included from /usr/src/promethean/kernel/usbpromethean.c:55:0:
/usr/src/promethean/kernel/usbpromethean.h:37:6: warning: conflicting types for built-in function 'round' [enable$
/usr/src/promethean/kernel/usbpromethean.c: In function 'usb_activ_thread_process_pipe_data':
/usr/src/promethean/kernel/usbpromethean.c:2493:21: error: implicit declaration of function 'err' [-Werror=implic$
/usr/src/promethean/kernel/usbpromethean.c: In function 'usb_activ_probe':
/usr/src/promethean/kernel/usbpromethean.c:2985:5: warning: format '%d' expects argument of type 'int', but argum$
cc1: some warnings being treated as errors
make[2]: *** [/usr/src/promethean/kernel/usbpromethean.o] Error 1
make[1]: *** [_module_/usr/src/promethean/kernel] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-3.6.6'
make: *** [all] Error 2
Probably, like I have read in another post: kernel 3.x is not supported at all so even if the driver still compiles Vs 3.4 kernel, it doesn't work. I hope that you are working on an update to the Activinspire packages and the drivers, given the next Debian release is coming soon.