[Fizzlemizz]

On closer look, you're creating all your functions a globals. While that's entirely up to you, the global space is shared by all other 3rd party addons and the the Blizzard UI. Blizzard tends use the more common names so it's up to addon authors to make whatever they place in the global table unique.

function eventHandler(self, event, ...)
   ...
end

Last addon loaded to use this as the name of their eventHandler function possibly gets to run all other addons events that use the same function name.

Use something like the addon name or abbreviation or ... to make globals unique:

function AMine_eventHandler(self, event, ...)
   ...
end

or use locals:

local function eventHandler(self, event, ...)
   ...
end

are two options.