<p>The assembly it's trying to find isn't the root assembly - it's a referenced one, but it's in the same folder, and Directory.GetCurrentDirectory() is the folder with all of the files in.</p>

<p>I'm stuck - any suggestions?</p>

You can either:
Create a new
```
AppDomain
```
to load the assembly (and set the
```
AppDomain
```
's base directory to the directory containing all the assemblies).
Attach a handler for
```
AppDomain.AssemblyResolve
```
to help the CLR find the assembly's dependencies.
You might be able to add the directory in question to the list of paths to probe. However, it will need to reside somewhere under your application's directory. See the
probe
element for more info.