Help please - Polycom 501 wont answer with Astrisk

Im running a very basic setup with a Polycom 501, TDM400P and Asterisk. I’ve tried for days and I can’t even get the Polycom to ring.

Astrisk (Zap) Picks up just fine, but when I try to call the SIP phone, nothing happens:

– Starting simple switch on 'Zap/4-1’
Oct 20 15:17:02 NOTICE[17878]: chan_zap.c:6000 ss_thread: Got event 18 (Ring Begin)…
– Executing Answer(“Zap/4-1”, “”) in new stack
– Executing Dial(“Zap/4-1”, “Zap/1|2|t”) in new stack
– Called 1
– Zap/1-1 is ringing
– Zap/1-1 is ringing
– Nobody picked up in 2000 ms
– Hungup ‘Zap/1-1’
– Executing BackGround(“Zap/4-1”, “wm-welcome-1”) in new stack
– Playing ‘wm-welcome-1’ (language ‘en’)
== CDR updated on Zap/4-1
– Executing Dial(“Zap/4-1”, “SIP/160@192.168.0.68:5060”) in new stack
– Called 160@192.168.0.68:5060
Oct 20 15:17:08 WARNING[17878]: chan_sip.c:2494 sip_write: Asked to transmit frame type 64, while native formats is 4 (read/write = 4/4)
== Spawn extension (incoming, 160, 1) exited non-zero on ‘Zap/4-1’
– Hungup ‘Zap/4-1’

Here is my SIP.config:

[160]
type=user
context=dialout
mailbox=160
username=160
secret=****
disallow=all
allow=alaw
allow=ulaw
allow=g729

[160]
type=peer
context=webmagic
host=dynamic
username=160
secret=****
defaultip=192.168.0.68
callerid=“Dave” <160>
mailbox=160
disallow=all
allow=alaw
allow=ulaw
allow=g729

So many sites make configuration seem so simple, but nothing is working. Can someone please give me any ideas?