Thank you for your answer, Vasilis.
I can access my database through PhpMyAdmin. Everything seems to be alright. However, I've chosen all the tables related to Game module and tried to repair them, but unfortunately I've obtained this message: "The storage engine for the table doesn't support repair."
I have very limited experience with mysql and I don't know what else could be done. Any ideas?
ευχαριστώ
Does the problem exists?
I checked again and I can't reproduce the problem.