Mate, could I suggest not trying to do a Diablo like clone, esp. in as2.

I've done a procedurally based RPG, and it's insane amount of work. Even with the game generating the content on the fly there's still loads of content you need to put in there, and that's once the game engine itself is working.

I'd recommend biting the bullet, get yourself a copy of Flash Develop, download Flixel and start making something relatively simple in as3.
There's nothing more inspiring than finishing a game, a 100 pretty prototypes don't count for anything.

Squize.