B1iSN updating Single UDF Field(s)

Dear Experts ,

I've encountered a problem trying to update existing document from F.FileSystem Object to B1.8.8 Object. I'll elaborate . I Hope you'll be able to help me.

I'm trying to update single field in existing invoice document.

this is my setup :

Sender System : F.AnyFileSystem

Reciever : B1.8.8

S.Object : FileIn

R.Object : Invoices_Object_13

when trying to update using static values of target invoice docEntry in the system I get the following error :

com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: com.sap.b1i.bizprocessor.BizProcException: BPE001 Nested exception: com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: java.lang.RuntimeException: DI Error: (-5002) 10000111 - On "Contents" tab, enter item or items

Any help would be much appreciated.

Thanks In advance,

NC.