I had the same error. Could this be a problem with the 'newui'? Seemed to me I recieved this error when new lines were added to the 'chat'.

My log:

MIXX-PC, 13.08 2015 11:37:18
Wrong parameter value
Class: 'Chat'
Function: 'Add'
Stack trace:
Scripts/GUI/Chat.c:144
Scripts/mission/missionGameplay.c:239
Scripts/DayZGame.c:275

Workbench mode
CLI params: C:\Games\steamapps\common\DayZ\DayZ.exe cpucount 4 exThreads 7 high newui nologs nosplash window