I am running Win7 x64. In order to open the character.db file successfully. I needed to download and replace the System.Data.SQLite.dll with the version from:
http://system.data.sqlite.org/downloads/1.0.87.0/sqlite-netFx40-static-binary-bundle-Win32-2010-1.0.87.0.zip
My build target is the default 32-bit Debug.
However since the build is for 32 bit it requires the 32bit .DLL AFAIK.