If you invoke a method and you get an error that says that the input argument types do not match, the method that you want to invoke was found but the arguments are not correct. Make sure that you use the correct data types in your script.
If you use the LoadAssembly method in your script to load an assembly into the AUT, another reason for this error might be that your assembly is built against a different version of the third-party library than the version that is used by the AUT. To fix this problem, change the referenced assembly in your project. If you are not sure which version of the third-party library is used in your AUT, you can use the Process Explorer tool from Microsoft.