#1 - 2011/09/28 07:41:00 AMIn 4.3 PTR it appears dividing by 0 is no longer working
local inf = 1/0
local serNaN = tostring(0/0)
or other similar number or hacks. A lot of mods are using these and they are not functional on PTR.
Intended change, or just a bug, don't know yet. Have to wait and see what blizzard says about this.