My guess on this is that the device files /dev/slamr* do not exist. These should have been created at installation or by init scripts. For me the debian sl-modem-daemon and sl-modem-source work. I looked through them, the installation script creates /dev/slamr* and /dev/slusb* (i guess for USB modems) thus:
mknod -m 660 /dev/slamr0 c 212 0
mknod -m 660 /dev/slamr1 c 212 1
...
and chown root.dialout /dev/slamr[0-3]
similiarly for /dev/slusb:
mknod -m 660 /dev/slusb0 c 213 0
...
and chown root.dialout /dev/slusb[0-3]
The debian init script also checks for intel8x0m ALSA module present in kernel >= 2.6.5 and uses it if present instead of slamr module; though i have not checked if it works (with intel 537 82801 AC'97 modems i suppose).
I am attaching a modified debian init file (sl-modem-daemon) for others after removing the debianism's from it. Also attached is a sample default file (sl-modem-daemon.default) which contains some options such as country; please rename as /etc/default/sl-modem-daemon to enable usage by init script (or obviously anywhere else after appropriately modifying the init script).
Check if this works; it seems that the init script does not handle slusb yet.