As I talked about recently, the standard binaries for db4o have some issues with mono, so I recompiled the unmodified source with the MONO configuration flag. I’ve packed up both the debug and release binaries and you can get them here. These are just the binaries (plus license). It’s not the full db4o package. If you want the full package, just get it directly from the db4o site, since the MONO config flag and have Visual Studio rebuild the package.
This package should show up on the official db4o mono page shortly as well.