Thank you all for your reply.
I don't make any change to the script, just downloaded and uploaded, make this twice or more and still the same issue. I check the index.php also replace it with the index.php from the other faucet that I have live and running with no problem. I starting to believe that the problem it's from my hosting, maybe don't support two sites to make sessions, I really don't know...
it's little strange if you still have problem although uploaded your script twice, what hosting did you use and how many site that supported in that hosting? i use namecheap shared hosting with 3 slot of add on domain and never get any problem with it.