[ns] problems after tampering with the queue

[Luqman]

hello,

I like to do some modifications to the ns code (2.30 with eurane) and
face some strange problem when I dequeue a packet from the
retransmission buffer, change a parameter (a new counter added by
myself to hdr_rlc structure) and enque the packet at the original place.


Simulation runs normally sometimes and the next time it stops with varying 
warnings and errors.

1) ns: scheduler going backwards in time from 11.900015 to 11.899000.
2) Scheduler: Event UID not valid!
3) Direction for pkt-flow not specified; Sending pkt up the stack on
default.

Segmentation fault (core dumped)

I just took a packet from the queue, changed the retransmission counter
and put that packet back on the queue at the same place. Nothing else
was changed.

Any ideas?

-- 
Luqman