Get grenade ammo

[Earliboy]

Hello,
i found a error message from my shop about the grenades:

Unknown weaponslot name frag_grenade_american_mp. Valid weaponslots are "primary" and "primaryb": (file 'maps/mp/gametypes/_shopping.gsc', line 781)
nades = self getWeaponSlotClipAmmo(grenadetype);

Currently it can't work cause i dind't changed the grenades max ammo to unlimited. But still i need to get the ammo of grenades.

giveGrenades(count)
{
	self takeweapon("frag_grenade_american_mp");
	self takeweapon("frag_grenade_german_mp");
	
	if(self.pers["team"] == "allies")
		grenadetype = "frag_grenade_american_mp";
	else
		grenadetype = "frag_grenade_german_mp";
	
	nades = self getWeaponSlotClipAmmo(grenadetype);
	count = count + nades;
	
	self giveWeapon(grenadetype);
	self setWeaponClipAmmo(grenadetype, count);
}

Any idea?