In your table
dbo.Sup_Item_Cat, it has a foreign key reference to another table. The way a FK works is it cannot have a value in that column that is not also in the primary key column of the referenced table.
If you have SQL Server Management Studio, open it up and
dbo.Sup_Item_Cat‘. See which column that FK is on, and which column of which table it references. You’re inserting some bad data.
Let me know if you need anything explained better!