Alright... one major problem with this script I can see so far... I'm using a caterpillar script for my party, so among the two options of drowning on or off -
If drowning is FALSE, then every time a character tries to go onto a water panel (and by the script, is immediately pushed one step backwards), the party member behind him goes onto the space where the leader just was - so you have the leader of the party unable to go into the water, yes, but all the other members are standing there on the water.
If drowning is TRUE, there are two concerns - every time you walk on a bridge over water or anything, the screen flashes red as if you were about to drown. Aside from that, if the water is only one panel wide and the character walks into it, the screen flashes red and the character jumps forward two panels - OVER the water into an area that should be inaccessible, at least for the time being. ;/