Crashing to desktop. Clueless.

[Mokaikai]

So a long time ago I created a mod based off dodgeding. Real simple mod. However recently I wanted to make it friendly for classes other than hunter. The basic premise is When a hunter dodges or parries they get a screen splash and audio signal they need to active mongoose bite or counter attack respectively. Since i was going through the steps to ensure it did nothing for other classes. I decided to add in functionality for warriors with overpower and rogues with disarm. However now this incredibly simple mod crashes to desktop whenever its triggered by event. I can't see why or how its not a very complex mod.

Any help would be greatly appreciated.

LUA script :

function MM_OnLoad()
	this:RegisterEvent("UNIT_COMBAT")
end

function MM_OnEvent(event)
	local playerClass, englishClass = UnitClass("player")
	if ( playerClass == "Hunter" ) then
		if (( event=="UNIT_COMBAT" ) and ( arg1=="player" ) and ( arg2=="DODGE" )) then
			PlaySoundFile("interface\\addons\\mongoosemania\\waves\\dodge.wav")
			MMMsgFrame:AddMessage(format("Mongoose Bite!"), 1, 1, 0, 1, 2)
		elseif (( event=="UNIT_COMBAT" ) and ( arg1=="player" ) and ( arg2=="PARRY" )) then
			PlaySoundFile("interface\\addons\\mongoosemania\\waves\\parry.wav")
			MMMsgFrame:AddMessage(format("Counter Attack!"), 1, 1, 0, 1, 2)
		end
	end
	if ( playerClass == "Warrior" ) then
		if (( event=="UNIT_COMBAT" ) and ( arg1=="target" ) and ( arg2=="DODGE" )) then
			PlaySoundFile("interface\\addons\\mongoosemania\\waves\\dodge.wav")
			MMMsgFrame:AddMessage(format("Overpower!"), 1, 1, 0, 1, 2)
		end
	end
	if ( playerClass == "Rogue" ) then
		if (( event=="UNIT_COMBAT" ) and ( arg1=="target" ) and ( arg2=="PARRY" )) then
			PlaySoundFile("interface\\addons\\mongoosemania\\waves\\parry.wav")
			MMMsgFrame:AddMessage(format("Disarm!"), 1, 1, 0, 1, 2)
		end
	end
end

XML file :

<Ui xmlns="http://www.blizzard.com/wow/ui/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.blizzard.com/wow/ui/">
	<Script file="MongooseMania.lua"/>
	<Frame name="MMAudioFrame">
		<Scripts>
			<OnLoad>
				MM_OnLoad()
			</OnLoad>			
		</Scripts>
	</Frame>
	<MessageFrame name="MMMsgFrame" insertMode="TOP" parent="UIParent" frameStrata="LOW" toplevel="true">
       	<Size>
			<AbsDimension x="512" y="60"/>
		</Size>
        	<Anchors>
				<Anchor point="CENTER">
					<Offset>
						<AbsDimension x="0" y="0"/>
					</Offset>
				</Anchor>
			</Anchors>
			<Scripts>
				<OnLoad>
					MM_OnLoad()
				</OnLoad>
				<OnEvent>
					MM_OnEvent(event, arg1, arg2)
				</OnEvent>
			</Scripts>		
		<FontString inherits="GameFontNormalHuge" justifyH="CENTER"/>
	</MessageFrame>	
</Ui>

WOW error:

This application has encountered a critical error: ERROR #132 (0x85100084) Fatal Exception Program: C:\Program Files\World of Warcraft\WoW.exe Exception: 0xC0000005 (ACCESS_VIOLATION) at 001B:00739967 The instruction at "0x00739967" referenced memory at "0xFFFFFFFC". The memory could not be "read".