Just to let all know that I finally added the following to the app.exe.config file where codeBase specifies the location:
<
runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="yyyyyy" publicKeyToken="fffffffffffff" culture="neutral" />
<codeBase version="0.0.0.0" href="subfolder/yyyyyy.dll"/>
</dependentAssembly>
</assemblyBinding>
</runtime>