From what I saw I found two issues:
The "_x select 3" for setVectorDirAndUp is incorrectly defined. It should be an array with two arrays like this: [[0,0,0], [0,0,0]] (BIS Wiki) createSimpleObject doesn't accept the same parameters as createVehicle, only model and location. (createSimpleObject, createVehicle)
Here is a working version (Changes are on lines 3 & 8):
private ["_objs"];
_objs = [
["a3\structures_f_bootcamp\items\electronics\watercooler_01_f.p3d", [0,0,0], 79.358, [[0,0,0],[0,0,0]], false]
];
{
private ["_obj"];
_obj = createSimpleObject [_x select 0, [0,0,0]];
if (_x select 4) then {
_obj setDir (_x select 2);
_obj setPos (_x select 1);
} else {
_obj setPosATL (_x select 1);
_obj setVectorDirAndUp (_x select 3);
};
} foreach _objs;