I recieved a email from AutoDESK CER which said
"Dear Autodesk® Civil 3D® Customer:
We recently received an error report from you. While we have not yet determined the resolution to the error, we have determined that the latest maintenance update has not yet been installed for your product." (SP3)
Very odd as I had installed SP3 as soon as it was on the web.
---- export from Product information ---------
Product name: Autodesk Civil 3D 2007
Product version: A.116.0 (UNICODE)
Product service pack: SP3
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Has the service pack 3 changed since the first public release or has my application not taken on some files from the patch?