ULX related error on player join

[ms333]

I seem to be getting the following error on my server which runs the latest version of ULX and ULib:

Code: [Select]

[ERROR] addons/ulib/lua/ulib/shared/hook.lua:110: lua/includes/extensions/table.lua:710: bad argument #1 to 'pairs' (table expected, got nil)
  1. fn - [C]:-1
   2. unknown - addons/ulib/lua/ulib/shared/hook.lua:110

Some debugging seems to indicate the error happens right after PlayerSpawn is called, and some deep debugging shows it happens right before the PlayerSpawn hook with the unique: ULXRagdollSpawnCheck is called. I don't know if this helps anything and I haven't been able to find the issue myself.
Some pointers to how I could find the cause would be nice.

[ms333]

I finally located the issue to be a PrintTable call with nil as #1 argument.
Because of the shitty stack trace, I had to add function call tracking to table.GetKeys where the above error came from. It led me to util.lua where PrintTable is defined and with more tracking, I was able to locate the place where it started.
So much just because of an annoying error with no info.