There are many ways to set up a conditional value list (I have a demo file that shows 10 different approaches), so it would help to know exactly how you have set this up, both in terms of relationships and options selected in the Manage | Value Lists dialogs.
Also, what data type is the field you have set up with this value list?
And what is the value that you expect to see? A Number or Text of some sort?
Yes I used your method to create this conditional value list!
field value list
PurchaseOrders::Type -> TypeOfItems
PurchaseOrders::Category_Shop -> CatOfItems
Transactions::Item -> NameOfItems
And the expected value should be Text
But exactly which field is set up with this value list? Transactions::Item?
And your portal on the layout is to Transactions?
With the layout based on Purchase Orders?
If so, I'd like to see the precise set up details for the NameOfItems value list--which is a dialog that you did not upload here.
Do you have an auto-enter field option on the Item field? And this is the item field, not the Item ID field in transactions that is set up with this value list?
Yes, field PurchaseOrders::Type is set up with TypeOfItems value list. Field Category_Shop field is set up with CatOfItems value list and field Transactions::Item is set up with NameOfItems. And the layout is in PurchaseOrders but the portal is Transactions and all the fields in the portal are transactions based.
NameOfItems Value List:
Use values from first field - Inventory 3::Item and Include only related values STARTING from: PurchaseOrders 4
TypeOfItems Value List:
Use values from field - Inventory 3::Type and Include all values
CatOfItems Value List:
Use values from first field - Inventory 3::Category_Shop and Include only related values starting from: PurchaseOrders 5
And no there is no auto enter field on the item field in the portal. And yes this is the Transactions::Item field NOT ItemID
Does the value list display the correct list of values when you go to select a value?
What data types are the item fields in Inventory and Transactions?
Yes the value list displays the correct values when selected, only once clicked does it change the value to the number. And by data types if you mean Text, Number, Date, Calculation ..etc Then Inventory::Item is a Text type and Transactions::Item is a Number type. Could this be the source of the problem?
Playing around with the types, I've found that changing the Number type to Text type made the portal work again. I'm not sure if the solution is fixed, but it does indeed work. Could explain why having two different data types caused such an error?
I suspect that selecting the field in the portal and changing the number data formatting from "as is" to some other setting such as "General" also would have corrected this issue.