Hello Francisco,
I have few advices.
1. Please, check if the server is properly configured. From the
Samples by Platforms section choose your platform and you will find the instructions how to configure your application correctly. It usually helps.
2. If it does not help try to use a special helper script called ExtractFiles which is posted
here. It could be used to check what really comes to the server. You will find description there.
Sincerely yours,
Alex Makhov