sporadic crash

Hi all ,
Lately we've been having an usual problem with radiusd on one of
our most critical production servers , the problem begins with
the sudden timeout of radiusd children with the log msg :
"Child exiting on timeout" , however we've also noticed that the problem
only occurs when these children timeout without returning their statuses :

Dec 12 00:59:31 Auth.info: Child exiting on timeout.
Dec 12 00:59:31 Auth.info: Child exiting on timeout.
Dec 12 00:59:31 Auth.info: Child exiting on timeout.
Dec 12 00:59:31 Auth.info: Child exiting on timeout.
Dec 12 00:59:31 Auth.info: Child exiting on timeout.
Dec 12 00:59:31 Auth.info: Child exiting on timeout.

this is followed by a complete "hang" of radiusd and it would have to be
restarted to start functioning again .

we're using  :
-  GNU radius version 1.2
-  Customly developed authentication program called through
Exec-Program-Wait
-  Customly developed accounting program called through Acct-Ext-Program

Any suggestions on how to deal with this problem ?