i downloaded jcow 1.3.5 and i registered my site with it... after the installation completes.. i tried to go to my site.... it says cannot connect to mysql server....

It's a permission issue on your server.
todo:
change permission of the following files&folder to "777":
"/my/config.php"
"/uploads/"
clear the database or choose a new database,
and re-install

.... what you said didn't work

according to another thread of yours, the issue has been solved.