marketpress not working in other languages

I have followed instructions 100% to get marketpress from english to italian. i am the web manager for this client and have not been able to get the store in italian.
my client is considering requesting a refund and is not please with the results.
I need urgent help resolving. I am an experienced programmer and have tried EVERYTHING without success. the software marketpress will not change language.
Please can you go on the server and resolve the issue?
My client will not upgrade, as i too agree that the purchased software is not actually working as it should.
Please get back to me as fast as posible. My name is David, Elisabeths web manager.