random number problem

Dear FLUKA experts,

when running relatively long (>1000000 events) runs I
often encounter the problem that an error happens
leading to the run abortion, and the number of events
before the run stops depends on the random seed number,
and varies from thousands to billions of events. I am
attaching the output file. Can you, please, suggest how
to overcome this problem?

-- 
best regards,
Vitaly