Props falling through world???

[Iron Herald]

Started up gmod today and suddenly couldn't spawn anything.
Well, I can spawn stuff but nothing seems to have any collision, can't grab anything with the physgun and every prop/entity just sinks through the ground and disappears, not too many errors in the console but one caught my eye:

[addons\wire\lua\wire\updatecheck.lua:45] attempt to concatenate local 'v' (a nil value)
ERROR! Module 'zlib_b64' not found!
Executing listen server config file
exec: couldn't exec listenserver.cfg
InitFastCopy: only 51% fast props. Bug?

Any ideas? oO

[editline]25th January 2011[/editline]

Problem solved, gmod was out of date, working fine now :)