asterisk users - Aug 2009 - dahdi_pri_error No more room in scheduler

Hi,
I suddenly started to receive an error like
[Aug  4 14:26:57] ERROR[2477]: chan_dahdi.c:10515 dahdi_pri_error: No more
room in scheduler
[Aug  4 14:26:57] ERROR[2477]: chan_dahdi.c:10515 dahdi_pri_error: Asked
to delete sched id -1???


and it went on till i reboot asterisk and dahdi services..
I wonder what caused this error, because there were no physical problem
between pbx and asterisk about the physical interfaces..

And is there an automated solution to restart the services or anything
else in this case???