I spent two hours resolving this issue today. I was trying to resurect some tests from an old test project that I hadn't created.
The failing line of code was:
static Database profilesDB = DatabaseFactory.CreateDatabase("profiles");
This project was using the Microsoft Enterprise Data Block version 5.0. I'm posting this solution because it was the only one that worked, after trying a dozen other things. Add the following to your App.config file:
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<qualifyAssembly partialName="Microsoft.Practices.EnterpriseLibrary.Data" fullName="Microsoft.Practices.EnterpriseLibrary.Data, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</assemblyBinding>
</runtime>
Joy!