Textures cannot exist on their own, they need to belong to a frame. You also have no need to use XML (most addons don't). Finally, you don't need a separate frame for each event you want to register. (And as a sidenote: semi-colons, while harmless, are not needed in Lua.)
lua Code:
local frame = CreateFrame("Frame", nil, UIParent)
frame:SetPoint("TOPLEFT", 567, -3)
frame:SetSize(127, 136) --this is an alias function to frame:SetWidth(127) and frame:SetHeight(136)
local texture = frame:CreateTexture()
texture:SetTexture("Interface\\AddOns\\Consuela\\consuela")
texture:SetAllPoints() --we'll anchor all of the texture's corners to its parent's, the frame above
texture:Hide() --we'll hide this for now until you want it shown
local function eventHandler(self, event, ...)
if event == "PLAYER_REGEN_DISABLED" then
PlaySoundFile("Interface\\AddOns\\Consuela\\comeget.mp3")
else
PlaySoundFile("Interface\\AddOns\\Consuela\\pledge.mp3")
end
end
Oh yeah, and frames don't need to be named, unless you wish to reference them outside of the file they are created in.
WoW only recognizes the .tga and (native) .blp formats for images. Not .png - you'll need to convert your texture. Also, make sure that the dimensions of your texture are a power of two (ex: 2,4,8,16,32,etc). The width and height don't have to match, and it can be up to 1024 px, iirc.
I don't know when you want your texture shown/hidden, so I haven't included that part.
/edit: fixed path to texture to escape \