well at first glance the drop command requires 19 parameters and each drop command in the script you supplied has 20...
i shall investigate to see what's what, and return your mini mission in full working order - hopefully
edit - well, it seems the error is "type number, expected array"... in the meantime, may i respectfully suggest
this fire script - it's the one i use and simplicity to call in a mission. it also works
edit 2 - all done. i added a tiny pause too as the script was lagging like crazy. see attached.