Hmm, I dont know enough about perl myself to offer up a fix, but you have the right idea.. look into reading/writing files with perl. it should be as easy as writing a timestamp when the event fires and specifying a time limit till it can fire again.

PS, if you are doing this on a *NIX system, use mplayer with the --quiet flag. I'm not sure if there is an equivalent for windows systems, but you should look into playing .mp3s from the windows CLI, as loading up vlc to play a file is a resource hog.