You need to make sure you're not already playing the node.
if IsButtonBeingPressed(6,0) and not PedIsPlaying(gPlayer,"node",true) then
PedSetActionNode(gPlayer,"node","file")
end
Or like I told you before, this will make sure you're not playing any action beside the idle/moving ones.
if PedMePlaying(gPlayer,"Default_KEY") then
-- code here
end