Alessandro,
We'll gladly help, but we'd need a lot more information on how to diagnose the issue. Can you let us know:
* What version of SCLogin were you using previously, if you know?
* Do you have SEF URLs enabled? If so, can you disable them and test if that works?
* Can you post a URL for us to see the problem? Without seeing the problem, it's very difficult to diagnose.
Thanks,
Alex