asterisk users - Jan 2005 - My dialplan just stopped working one day

Hrm,

All of a sudden for some reason Wait() and Playback() are returning
non-zero and its causing calls on my inbound SIP leg not to complete.
I'm not sure why

   -- Executing Answer("SIP/2181-4518", "") in new stack
   -- Executing Playback("SIP/2181-4518", "silence/1") in
new stack
   -- Playing 'silence/1' (language 'en')
 == Spawn extension (inbound, 2181, 2) exited non-zero on
'SIP/2181-4518'
   -- Executing Hangup("SIP/2181-4518", "") in new stack
 == Spawn extension (inbound, h, 1) exited non-zero on 'SIP/2181-4518'

Extentions.conf:
[default]
; Main menu
exten => main,1,Background(thank-you-for-calling)
exten => main,2,Background(silence/1)
exten => main,3,Background(if-u-know-ext-dial)
exten => main,4,Background(silence/1)
exten => main,5,Background(for-tech-support)
exten => main,6,Background(press-1)
exten => main,7,Background(silence/1)
exten => main,8,Background(to-hear-menu-again)
exten => main,9,Background(press-9)

exten => h,1,Hangup
exten => t,1,Goto(default,main,1)
exten => i,1,Playback(invalid)
exten => i,2,Playback(goodbye)
exten => i,3,Goto(default,main,1)
exten => T,1,Playback(goodbye)
exten => T,2,Hangup

; Use dialed an extention
exten => _2XXX,1,Goto(extentions,${EXTEN},1)

[inbound]
; This is the list if inbound lines
exten => 2181,1,Answer
exten => 2181,2,Playback(silence/1)
exten => 2181,3,Goto(default,main,1)
exten => 2181,3,Hangup

exten => h,1,Hangup
exten => t,1,Hangup
exten => i,1,Hangup
exten => T,1,Hangup

[extentions]
exten => 2000,1,Dial(SIP/2000,20)
exten => 2000,2,Voicemail(u2000)
exten => 2000,102,Voicemail(b2000)
exten => 2000,103,Hangup

exten => 2001,1,Dial(SIP/2001,20)
exten => 2001,2,Voicemail(u2001)
exten => 2001,102,Voicemail(b2001)
exten => 2001,103,Hangup

;exten => 2002,1,Dial(IAX2/iaxphone,20)
;exten => 2002,2,Voicemail(u2002)
;exten => 2002,102,Voicemail(b2002)
;exten => 2002,103,Hangup

exten => 2999,1,VoicemailMain(${CALLERIDNUM})

exten => h,1,Hangup
exten => t,1,Hangup
exten => i,1,Playback(invalid)
exten => i,2,Goto(default,main,3)
exten => T,1,Playback(goodbye)
exten => T,2,Hangup
exten => s,1,Goto(default,main,3)

Sip.conf:

[general]
bindaddr = 0.0.0.0
allow = all
context = bogon-calls
register => 2181:yoyoyodawg@66.165.175.227/2181

[2000]
type=friend
username=2000
secret=yoyoyodawg
host=dynamic
nat=yes
canreinvite=no
context=outbound
mailbox=100
disallow=all
allow=gsm

[2001]
type=friend
username=2001
secret=yoyoyodawg
host=dynamic
context=outbound
mailbox=101
nat=yes

[2181]
type=friend
secret=yoyoyodawg
host=66.165.175.227
context=inbound
canreinvite=no
dtmfmode=rfc2833
disallow=all
allow=gsm
allow=g729
allow=ilbc
allow=speex
allow=ulaw
allow=alaw
username=2181
fromuser=2181

> [inbound]
> ; This is the list if inbound lines
> exten => 2181,1,Answer
> exten => 2181,2,Playback(silence/1)
> exten => 2181,3,Goto(default,main,1)
> exten => 2181,3,Hangup
Notice there are two "2181,3" entries.