Why would you need this script at all if you can just put ammo there to pick up? Anyway...
You are using the plrtake all wrong (no path)... and it's playertake.
Have a look in the 'pickup' files in your scriptbank for examples.
You could use a trigger at the tech to do the AI for him, and assign the ammo in the IFUSED of the trigger.
(The alternative to the trigger is to add an IFUSED assignment to the character's FPE)
If you place the ammo in front of your Tech and set spawn at start to no, then it will appear when activated.
The Ammo is specific to the Gun being used as described in the ammo's fpe.
So, unless the player can only carry one type of gun, your Tech won't be much help.
The solution to that is give the player a weapon instead of ammo since it acts as ammo too.
That way it won't matter if he has a gun yet or not.