Unity IoC: Where to place the assembly?

I have a few Assemblies: MyInterfaces.dll, MyImplementations.dll, MyTestApp.exe

In my config I do the mapping but I get the following error during runtime:

The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)

My question is:

Do I need to register my two assembly in the GAC or do just the /bin folder of MyTestApp? Otherwise what am I doing wrong?

The assemblies should just have to be accessible to your app through any of the "normal" means (in the GAC, in the same directory, etc).

Are you using fully-qualified assembly names in your config? Like:

MyInterfaces, Version=1.2.3.4, Culture=neutral, PublicKeyToken=b77a5c561934e089

You could try using the Fusion Logger to see what is happening too.