I didn't find any technical problems with the triggers, they seem to do what they are supposed to. There is one flaw however about the reinforcements on both sides which just appear out of thin air, right on the battlefield. You should create them in the back and let them march up to the front line.
Or perhaps you shouldn't – the reinforcements are the big problem in this scenario. They arrive so fast that they clog up the battlefield. Within a minute or two there are huge numbers of soldiers and catapults around, way too many to reasonably control them. You would need to cut down the number of troops to arrive and make them arrive at longer intervals to make it playable. (Of course, there actually is no need to play the main battle at all - see below.)
Unless the player destroys his own temple it's impossible to lose. The reinforcements arrive way too fast and in too big numbers to leave the enemy any chance to break through, especially since the AI has no GPs at its disposal. (And no knowledge about how to win the scenario.)
Winning on the other hand is really easy if the player remembers rule number one for trench warfare: "Never get caught up in trench warfare".
The use of multiple Meteor GPs as 'artillery' was a good idea. I've never been shelled myself, but it looked pretty "realistic" to me. Apart from that we just have two big armies slugging it out, with minimal player control. Trying to create a WWI scenario for AoM is certainly unique, but personally I'd call it more absurd than creative.
Map Design: 4
The map looks quite good, especially the 'no man's land' between the bases. The bases themselves are nothing special, you should have invested a little more time here. The map does its job, but it's nothing to go "wow!" about.
There is no story, and the instructions are limited to a couple of messages right at the start. "Destroy the enemy temple" is clear, but hints like "there is a river" made me wonder why you would think someone could possibly miss that.
Btw, I've seen that you tried to use the objectives page. Just filling the form doesn't do the trick however, you have to add a trigger with effect 'objective' to make it accessible during the game.
The cow looks a little out of place on the battlefield, it might have been better to use a cinematic block instead. And a day/night cycle consists of more than two phases. You may want to take a look at the Scenario Design Tutorial here on the site for a complete day/night cycle that actually works.
Oh, and there is no need to put every file twice into the zip archive!