I\'ve been extremely frustrated trying to deploy a C#/WPF application I\'ve created that has some references to 3rd party DLLs.  I created a folder in the project, called 
You could try this which solved a similar issue for me:
Add the DLL's that are not .NET libraries to the solution as files:
Right click project > Add > Existing Item
Then set their build action to Content and "Copy to output directory" to "Copy Always".
That way the libraries will be included in the output directory.