chan_dahdi.c: CallerID returned with error

Hello all,
On occasion I get this in the asterisk message log:

WARNING[19897] chan_dahdi.c: CallerID returned with error on channel 'DAHDI/3-1’
NOTICE[19897] chan_dahdi.c: MWI: Channel 3 no message waiting!

I am unable to call out on Channel 3 and when I try to, I get this on the asterisk console:

WARNING[20247]: app_dial.c:1528 dial_exec_full: Unable to create channel of type ‘DAHDI’ (cause 0 - Unknown)
== Everyone is busy/congested at this time (1:0/0/1)
– Auto fallthrough, channel ‘SIP/phone’ status is ‘CHANUNAVAIL’

I also cannot call in on that channel. To get the channel back working, I just unplug that phone line and plug it back in. I don’t see anything in the call logs around the time this error occurs. This doesn’t happen very often. What could be causing this?

Here’s what I’m running:
DAHDI Version:
Digium Wildcard TDM2400P Board 1
OpenSUSE 11.1