The workaround for this issue will be to use a 10 Pre-Release client (ArcGIS Desktop, Engine or Server) to upgrade your geodatabases from 9.4 beta to 10 pre-release. Once your geodatabases have been upgraded to 10 pre-release, a 10 final client can then be used to connect to these geodatabases. You can then continue using the 10 pre-release geodatabase or upgrade it to 10 final as we recommend.