i am working on my new call of duty map, which involves a realistic gun/ammunition/reloading system. since there is a reloading time for each gun, i need triggers to stop the human player from attacking the computer player. i have already tried setting the alliance status so that the computer player is set to allies and preserved trigger. this works. however, the problem is, once i do this, the computer player stops attacking also, even though there is a preserved trigger that tells the computer player to set the human player to enemy.

any suggestions?

Well the solution is simple: Only run the alliance for the player.
You are probably running the set alliance to ally action for the comp too.

This shouldn't happen. Whether the computer is an enemy or ally to you doesn't affect whether you are an enemy or ally to the comp.

Condition: (for human players only)
Curren player accumulates exactly 0 gas. (guessing ammo count)
Action:
Set computer to ally.
Preserve.

If during the whole map you want the computer to attack you, you don't need to preserve it.

If I had to guess, the computer was probably ordered to Attack instead of Patrol. Computer units under Attack command will move towards their destination ignoring enemies UNLESS ATTACKED FIRST. Patrol is the better option.