I had exactly the same prob and I knw what to do,
$ uname -r
$ cd /usr/src/<result of uname -r>
$ make oldconfig #or 'make config' if u are very energetic
$make dep
#then
$ cd /home/<your dir>/pctel.9.6.......
$make clean
$configure --with-hal=.........
$make
$make install
$cd modules
$insmod pctel.o
$insmod ptserial.o
GOOD LUCK