I believe it's only the exec line. as you see...
_obj = _this select 0
_guns = _this select 1
_shells = _this select 2
_rvec = _this select 3
_delay = _this select 4
_sname = _this select 5
_ra = _rvec select 0
_vzr = _rvec select 1
_vz = _rvec select 2
_dir = getDir _obj
_odir = getDir _obj
you need:
[objectname,amount of mortars,amount of shells,[random x dispersion,random y dispersion,z-vector velocity],delay,"shellname"] exec "arty_strike.sqs"
straight rip from the file itself ;D You've just left out the amount of mortars or shells, and the vectors are entered in the wrong place. I know why... u've mixed versions 0.7 and 0.8. All you need is to enter what the exec line says in the file itself.
That should do it. That's the way they are in versions 0.8 and 0.9, except 0.9 has a script to enter the vectors after calculations. It's not very well done, as it counts down the z-vector velocity in a straight with an
if else line, as it should be a parabel or some sort of mathematical überFunky thingy, which I know nothing of.