Newbie with errors on hsf install...

hi...history of what is done: on a fresh install fedora core 3 on a dell
inspiron 8200. (luckily eth0 is up!)

did scan modem and found:
 The soft modem Subsystem operates under a controller
   8086:2486 82801CA/CAM AC97 ICH3
Also in the data file was this message I thought might be important...

 The kernel-2.6.9-1.667 was compiled with CONFIG_REGPARM, providing more
compact and faster code.

 The kernel was assembled with compiler:  3.4.2
 a gcc package must be installed to support driver compiling

Checking for kernel-headers needed for compiling.
 kernel-headers have base folder /lib/modules/2.6.9-1.667/build

 Modem symbolic link is:  /dev/modem -> /dev/ttyS1


Did the kernel .stk16 update....And then did the install. While
installing i got this error message on the web:

warning: hsfmodem-7.18.00.03full_k2.6.9_1.667.stk16-1fdr.i686.rpm: V3
DSA signature: NOKEY, key ID 5dfbf7dc
Conexant HSF softmodem driver, version 7.18.00.03full

If you need license keys, assistance or more information, please go to:
    http://www.linuxant.com/

When reporting a problem for the first time, please send
us the file generated by "hsfconfig --dumpdiag".

Pre-built driver modules that seem compatible with your system were
found under
/usr/lib/hsfmodem/modules/binaries/linux-2.6.9-1.667.stk16.
WARNING: renamed existing /dev/modem to /dev/modem.old:

lrwxrwxrwx  1 root root 10 Mar 10 15:54 /dev/modem.old -> /dev/ttyS1

ERROR: no device detected by hsf driver
error: %post(hsfmodem-7.18.00.03full_k2.6.9_1.667.stk16-1fdr.i686)
scriptlet failed, exit status 1


I downloaded the public key...but when i go to install it in terminal i
get this...
--import/pubkey unknown option

i am stuck! Can anyone point me in the right direction?
thanx!
J>