Help Subform Enter Parameter Value error

i have 2 form
main form = "TanggalF"
subform = "MerkFsubform"

i have a query with 2 field "Combo28" and "Combo30"
i use it in subform with query [Forms]![MerkFsubform]![Combo30]
Combo30 is combo box on MerkFsubform
if i open in subform "MerkFsubform" work, no problem

but if i open on main form "TanggalF" it get errror "Enter Parameter Value" Form!Merksubform!Combo30

How to solve this
Thank You