I have a Drupal 6 site. it has clean URL enabled. when I edit a profile it says page not found. but on the link when I add index.php?q=user, it works. but if that is not there I get an error.
after Google search I came to no its something about, clean URL, and apache config. but I cant seem to no what to do from here.
I have check this: https://drupal.org/getting-started/clean-urls
but still no luck
Which operating system are you using? You probably need to allow the webserver to overwrite.
Here are two examples (for Apache on Fedora and for Wamp server on Windows):
Linux (Centos) - Add the following to /ets/httpd/conf/httpd.conf:
<Directory /var/www/html/>
AllowOverride all
</Directory>
If you are using wamp server on windows, you should click the wamp server logo and select 'Apache -> Apache modules -> rewrite_module'
I haven't tried this on other operating systems myself but I guess it's the solution would be similar to this.