Error on Adding Item To Basket

Frekie

Hey All -
Working with a SQL Server 2000/Commerce Server 2000 and Navision 3.60 with customer database. There are no real modifications in the context.

Whenever a logged in CP Customer adds an item to his basket, I recieve an error stating that there was no reply from Navision.
The receive queue is filled with a message. The reply queue is not. So it enters Navision well but then it get's lost.

When checking the NAS events I have the error :
The SalesHeader does not exist.
Fields Captions : Document Type Quote Document No. 0

I traced it down to an error somewhere in the validation of No. in the Sales Line Table.

Has anyone encountered an error like this ? Any help would be usefull and certainly appreciated.

Deadlines are looming.