Function GetQuestId() currently does not exist. (?)
Lua error - Message: Interface\AddOns\xxx\xxx.lua:107: attempt to call global 'GetQuestID' (a nil value)
In addition, some sources say, to call the function with parameter
http://www.theromwiki.com/API:GetQuestId, but it changes nothing.
If the quest is in Quest Log, simply call the function:
http://wowprogramming.com/docs/api/GetQuestLogTitle
questID return direct from this function.