Minimum Purchase Error

Product:Quantity:Price:Total:FE-195- Caterpillar 3208 375 hp Single Turbo, Size 7 1/2" Base Diameter x 8" Tall Tapered Cone1$14.00$14.00FE-3304 Caterpillar 3304 Generator air filter, Size 9 1/2" Diameter x 6 1/2" Tall Strait1$12.50$12.50FE-202- BT903. Cummins BT903, size - 10″ Diameter x 6″ Tall Cylinder shaped1$14.50$14.50FE-3516- 3516 2500 hp, Size 19" Diameter x 13 7/8" Tall Strait1$19.25$19.25FE-6125A. Cummins 6125, Size, 12 1/2" Diameter x 9 1/2" Tall Strait Cylinder Shape1$14.00$14.00 (5) Error  Error => Minimum Purchase quantity of 6 units required for this group. (Rule ID = 541)