syslog warnings and error messages

Does anyone know where to look-up warnings and error messages to
find out what they are telling us ?
For instance I have this rather disturbing pair of messages in syslog:

gdm[7408]: GLib-CRITICAL: g_hash_table_lookup_extended: assertion `hash_table != NULL' failed

gdm[7408]: WARNING: Request for invalid configuration key xdmcp/Enable=false

 

There's mention of that one over on launchpad Ocky. Which version including full pkg name?

 

It's version 2.20.7-Oubuntu1.1(hardy-updates)
According to syslog occurs on shut-down.
Have not noticed anything untoward on shut-down - must have always been
'living' with it.
Will have a look - maybe a Hardy bug.
Thanks.
Edit:-
Had a look - it's a Hardy bug that has not been fixed yet. As I don't experience shutdown problems, I am
satisfied to wait for 8.04.3 release. https://bugs.launchpad.net/ubuntu/ source/gdm/ bug/249039

 

Yeah, that's the one. As long as you're not noticing any shortcomings, stay satisfied - it's sometimes easier.