Why not using some php-files for doing the important calculations on the serverside?

For example the file foundCoin.php is called if the player found a coin: The file asks the database if there is really a coin on the players field, add the coin to the players coins and echo 0 for error or 1 for success simply?

Any suggestions about the speed of this solution?

You can have a look at my JewelQuest codes. I also included the
php used. Im no php guy, so they are horrible, but work for
basic communication.
(server sends changed "world" data, client sends specific gamedata)

http://www.opserver.de/ubb7/ubbthreads.php?ubb=showflat&Number=310529#Post310529

For a game, as you describe it, php should be the perfect solution.
Also since there are free online servers that can handle the game.
Nicer that having to run a server yourself.

I worked on a flash project that did something similar to what you want to do. I wasn't the programmer but I know he used php to achieve the client database communication. The game takes part "live" and we were able to create a turnbased system within teams of players by synching them on start up. You can see how far we got on http://klimaxgame.nl, click on work in progress version. If you need help I could ask the programmer if he doesn't mind giving his email to you.

cartoon_baboon