I try to update an object from Tibco. While i try to do so I get the following error
I have ensured that I am updating the field directly and not through any parent relationship.
This error means that the field in question can't be updated as part of the API call. You'll get this error when you try to update a read-only field, such as CreatedById without Editable Audit Fields, or a master-detail field that does not allow reparenting of records. You'll want to check the field to see if it can be written to.