The DAAB is part of the Enterprise Library, but I guess can be install separately.
So to the reference issue. Are you trying to add a reference to it from the GAC or are you trying to reference the dlls directly?
If you application is .NET 2.0 for example you will most likely have issues referencing the latest version because it is .NET 3.5. You would need to get an older version of the DAAB.
You can find the dlls for the Enterprise library in the folder it was installed. You should see a src folder or something like that with a solution of all the source code. If you did not build them during installation you can just open the solution and build them yourself.