asterisk users - Nov 2004 - No incoming calls on skinny phone

Hi list!

My skinny phone can make outgoing calls but incoming calls just keep 
ringing for the calling end but the phone that actually should ring 
doesn't ring at all.

I guess I have something messed up with the dial command.

I have this in skinny.conf:
[z4040]
device=SEP000000000000 (actual number removed)
nat=0
callerid="z4040" <105>
callwaiting=0
mailbox=199
transfer=1
context=intern
line => 105


I have this in extensions.conf
exten => 105,1,Dial(Skinny/105@z4040,30,tr)
exten => 105,2,Playback(invalid)
exten => 105,3,Hangup
exten => 105,102,Voicemail(199)
exten => 105,103,Hangup


The asterisk console displays this at startup:
     -- Setting mailbox '199' on z4040@105
     -- Allocating Skinny subchannel '0' on 105@z4040
     -- Allocating Skinny subchannel '1' on 105@z4040

When I dial the device this shows up on the console:
Found device: z4040
     -- skinny_call(Skinny/105@z4040-2)

But the phone doesn't ring.

I don't understand a thing about the skinny protocol or the line stuff so 
maybe it's something obvious that I missed.

Thanks!!!