Strange behavior regarding saving documents

Hi,

We have a major problem regarding saving documents for a company, its a bit of a "come and go" issue that has escalated for the last few days.

The problem is that NSDocumentAgent saves the wrong document, and directly after its saved, it says that the document has been checked out by another user, (that does not have anything to do with the sale, or customer, or even country)

We have the exact same code in multiple enviroments, but, its only happening for this customer.

They are using Webtools, and SO for documents.

The code

NSListAgent listAgent;
Byte[] TheFileInByte = decodeBase64(getCgiVariable("base64"));
NSDocumentTemplate documentTemplate = listAgent.GetDocumentTemplate(346); 
NSContact contactEntity;
contactEntity.SetContactId(MyContact.toInteger());
NSPerson personEntity;
if(personId != "")
  personEntity.SetPersonId(personId.toInteger());

NSSale saleEntity;
DateTime now;
NSDocumentAgent documentAgent;
NSDocumentEntity documentEntity = documentAgent.CreateDefaultDocumentEntity();
documentEntity.SetName(saleName + '.docx');
//documentEntity.SetHeader('Abax-OrderProposal-v' + NewVersion.toString());
documentEntity.SetHeader(saleName);
documentEntity.SetContact(contactEntity);
documentEntity.SetPerson(personEntity);
documentEntity.SetSale(saleEntity);
documentEntity.SetDate(now);
documentEntity.SetDocumentTemplate(documentTemplate);
NSAssociateAgent associateAgent;
documentEntity.SetAssociate(associateAgent.GetAssociate(assId.toInteger()));

NSDocumentEntity FUSO = documentAgent.SaveDocumentEntity(documentEntity);
DocId = FUSO.GetDocumentId();
NSStream stream;
stream.SetStream(TheFileInByte);
documentAgent.SetDocumentStreamFromId(DocId, stream);

It crashes with the following message:
NetServerException: NetServer exception: Service call Document.SetDocumentStreamFromId failed

Document ID 2487527, extref is locked and not checked out to current user Checked out by <another user>

But, the document is created, and, the content in the file is something else, in this specific case, a quote from 34 days ago, for another customer, another sale and has nothing in common with the document created, or hasnt been opened or modified since it was created.

And, we have verified that the base64 that comes in is in fact the document we wanted to save.

Anyone have any experience or ideas regarding this?
Regards
Pär Pettersson