Hi,
DOCS Open 4 is not designed to work with new SQL Server versions. But you can try this workaround: This issue occurs because a separate SQL client does not exist for Microsoft SQL Server 2005. To resolve this issue, copy the NTWDBLIB.DLL file from a Microsoft SQL Server 2000 client to the %SYSVOL%\System32 directory on the DM server.
This works at least with some Hummingbird DM 5.x versions.