Hi guys, problem solved
here my feedback, hope it could be useful for someone:
After I understand that the issue was related to w3t_posts I opened the .sql with a text editor, deleted everything before w3t_posts and saved it as "PRE_W3T_POSTS.SQL", than open again the original .sql, removed everithing from the beginning to the end of w3t_posts and saved it as "POST_W3T_POSTS.SQL". Opened again and removed everything before and after w3t_posts and saved it as "W3T_POSTS.SQL".
After I created those 3 files used MySQL-Front to import all in my database. Obviously I got a problem with the w3t_posts one but MySQL-Front recorded a .err file with all operations failed.
I opened the .err and copied row by row and executed them in MySQL-Front...
DONE ! Now I have a perfect database again !
