asterisk users - Dec 2003 - D-channel down

Hi list,
	 
	This morning, my asterisk box (PRI trunk) just stops to make calls.

NOTICE[16401]: File app_dial.c, Line 506 (dial_exec): Unable to
create channel of type 'Zap

	without any reason. Now, asterisk doesn't brings up d-channel 

DEBUG[11276]: File chan_zap.c, Line 6410 (pri_dchannel): Got event No
event (0) on D-channel for span 1

 anyone could help?


thanks
Eduardo