You forgot one of the parameters with the explode (input string).
Also that kick didn't work for me, after look in how amx_kick can kick steamIDs
I learned how to kick them

here is what I did in the end:
Code:
new steamid[32][32];
ExplodeString(steamid,2,31,buf,'%');
//Handle Data
server_print("(SnapShooter) GOT PEOPLE TO KICK");
server_print("(SnapShooter) READ(%i bytes): %s",z,buf);
new i;
for (i = 1; i <= 32; i++) {
if (strlen(steamid[i]) > 5) {
new reason[43] = "(SnapShooteR) Please activate SnapShooter!";
new player = cmd_target(1, steamid[i], 0);
new userid = get_user_userid(player);
server_cmd("kick #%d ^"%s^"", userid, reason)
}
}