Sometimes commands that are run as soon as the game starts (ie in the init fields of a unit) don't work - they need a short delay - and switchmove seems to be one of them. you have a couple of options.-
1.) name the units you want to start off injured. Make a trigger, and change it's Activation field from 'this' to 'true', select the 'countdown' option, and in the min, mid and max boxes, put a small delay, such as 0.2. Then in the activation field, put this:
{_x switchmove "CombatDeadVer3"} foreach [unit1, unit2, unit3]
where unit1 and so on are the names you gave the units.
2.) create a new script.
;Animate.sqs
~0.2
(_this select 0) switchmove "CombatDeadVer3"
In each unit you want to start off dead, put the following: [this] exec "animate.sqs"
Apologies if you know all the coding stuff already. Just covering my bases in case you didn't