What errors are you getting?
I don't know anything about the 'health' message but I'm assuming that it does pass and id and that read_data(1) gives you the hp of that player.
So the only other error could be in displaying the hud message. I have no idea what all the numbers do, i just compared them with this
http://www.amxmodx.org/funcwiki.php?...sage&go=search
to see if all the data types matched. Maybe you need to set different numbers..