[cokedrivers]

I have a professions button that i use to open prof1 and prof2 when ever i leftclick for prof1 i get this:

9x [ADDON_ACTION_FORBIDDEN] AddOn 'BasicUI' tried to call the protected function 'CastSpellByName()'.
[string "@!BugGrabber\BugGrabber.lua"]:519: in function <!BugGrabber\BugGrabber.lua:519>
[string "=[C]"]: in function `CastSpellByName'
[string "@BasicUI\Modules\Datapanel.lua"]:1763: in function <BasicUI\Modules\Datapanel.lua:1752>

Yet if i right click the same button it opens prof2 like it is suppose to.

Here is the code im using:

		proPlugin:SetScript("OnMouseDown",function(self, button)
			local prof1, prof2, _, _, _ = GetProfessions()
			if button == "LeftButton" then
				if prof1 then	
					CastSpellByName((GetProfessionInfo(prof1)))
				else
					print('|cff33ff99BasicUI:|r |cffFF0000No Profession Found!|r')
				end
			elseif button == 'MiddleButton' then
				ToggleSpellBook(BOOKTYPE_PROFESSION)	
			elseif button == "RightButton" then
				if prof2 then
					CastSpellByName((GetProfessionInfo(prof2)))
				else
					print('|cff33ff99BasicUI:|r |cffFF0000No Profession Found!|r')
				end
			end
		end)

Why does the leftbutton throw and error yet the middle and right do not?