Over the last week, we've started to see the odd segfault (roughly one 
per day) with Slony, and I now have a coredump with better info...

Core was generated by `postgres: sharp laterooms 194.24.250.135(54478) 
UPDATE                        '.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libpam.so.0...(no debugging symbols 
found)...done.
....
Reading symbols from /usr/lib/postgresql/8.1/lib/slony1_funcs.so...done.
Loaded symbols for /usr/lib/postgresql/8.1/lib/slony1_funcs.so
Reading symbols from /usr/lib/postgresql/8.1/lib/xxid.so...done.
Loaded symbols for /usr/lib/postgresql/8.1/lib/xxid.so
#0  0x00002aaaab5e8c00 in strlen () from /lib/libc.so.6
(gdb) bt
#0  0x00002aaaab5e8c00 in strlen () from /lib/libc.so.6
#1  0x00002aaaca65b062 in slon_quote_literal (str=0x0) at 
slony1_funcs.c:1044
#2  0x00002aaaca65c348 in _Slony_I_logTrigger (fcinfo=0x8f5ec5) at 
slony1_funcs.c:783
#3  0x00000000005ca9f9 in fmgr_internal_function ()
#4  0x00000000004ce6a4 in FreeTriggerDesc ()
#5  0x00000000004cf42e in ExecARUpdateTriggers ()
#6  0x00000000004cf873 in ExecARUpdateTriggers ()
#7  0x00000000004cfb10 in AfterTriggerEndQuery ()
#8  0x000000000055ef05 in FreeQueryDesc ()
#9  0x000000000055fecf in PortalRun ()
#10 0x000000000055f78f in PortalRun ()
#11 0x000000000055b721 in pg_plan_queries ()
#12 0x000000000055e14c in PostgresMain ()
#13 0x0000000000539cc1 in ClosePostmasterPorts ()
#14 0x0000000000539797 in ClosePostmasterPorts ()
#15 0x0000000000537d3d in PostmasterMain ()
#16 0x000000000053704e in PostmasterMain ()
#17 0x00000000004fdb58 in main ()

Is there anything else I can do / provide to help debug this (given than 
I'm no coder!)

Cheers,
Gavin.