Mod suddenly doesn't Start!!

Hey Everybody,
I made a complete mod based on HTW, on ancient Italy (you know, Carthage, Rome, Etruscans, Insubres, etc.) (no campaign though) with all new factions, new units, new sound effects, flags, and entirely new music. It was the most perfect mod I've ever done- no ctd's- everything ran smoothly, and I finished it. Then the other day I was messing around with both the Projectilestats and, I replaced some ground textures for desert. Suddenly it wouldn't start! I can't remember doing anything else- so I replaced the stuff I had been working on (projectile stats), and even (quite idiotically) replaced all the loc/eng files with my loc/eng files from two weeks ago- without backing up the current stuff!
It still won't start, and it seems nothing I do can fix it. The more I try to figure it out and fix, the more I seem to be risking screwing it up more.
Does anyone have any idea what I did?
Thanks!
Justin