Why "Missing Value for…" in the cart?

[Studio 42]

Hi,
to clarify :
DO you use all 2, one page checkout from rupostel or 3 party compagny?
Perhaps this is a bad setting, i had same type of problem, because OPC settings.
Of course the message can come from a plugin or vm it self, because VM check for some fields for shipment and paiment, but perhaps OPC do not set this fields on ajax

Same problem has rajmohansoft and same setting
Virtuemart version : 3.0.9
     Joomla : 3.4.3
     Upgrad from : 2.5 to 3.4

One difference, message is "Missing value for Ship To state id"

This message appears if the buyer is a guest or if try to register or even if the user is already registered and the field  "State" is filled.

In this case (registered user with all fields filled) when get to shopping cart the dropdown "State" has no value.

You can look and try at kromalia.com