Try this to disable pick-up weapons.
Code:
#include <amxmodx>
#include <hamsandwich>
public plugin_init()
{
RegisterHam(Ham_Touch, "weapon_hegrenade", "player_touchweapon")
RegisterHam(Ham_Touch, "weaponbox", "player_touchweapon")
RegisterHam(Ham_Touch, "armoury_entity", "player_touchweapon")
}
public player_touchweapon(id, ent) return HAM_SUPERCEDE