Ok, as far as I read, you're allowed to use any delay. But I still thinks that it's wrong at that point.
But first to a fault:
onMapSingleClick "[[],Player,[],1,_pos] call ROMM_fPara; true
;"
The last ';' has to get removed because true should be a return value. Currently there is no return value and according to Biki that will raise an error message:
In such case default processing by the game engine is done, and error message may be displayed
But nevertheless:
onMapSingleClick has to wait until player hit the ground. If you use spawn it don't has to wait and your script still runs.