OK, why don't you test the scripts one by one?
1. Create your player and name it "mychar", thne create a soldier that you want to kill and test your script.
2. in the init field of the to be killed soldier, write down "this addEventHandler ["killed", {_this exec "delbody.sqs"}]"
3. Put a debug message below the "_u = _this select 0" in delbody.sqs something like:
"mychar globalChat "delbody.sqs got called";
mychar globalChat format ["%1 got killed", _u];"
4. if you recieve a message, and the guy who got killed is the guy you killed then it means that it got called and the "_u" variable is correct.
5. If the soldier doesn't die, change the ~60 to ~2 or simply delete the whole line to see if it's the time delay that's causing the problem.
btw, "_u setpos [0,0,99999]" doesn't help you at all, it dosn't reduce the lag or cpu load if not increase it, so I suggest you to remove it.
Once you're sure this script works, keep the debug message and I can show you how to test the other script.
I can't test your script where I am (since I don't have OFP installed at work) so I can only give you advice
.