As suphp is running in Mellowhost thats why sometimes permission problem occurs while installing drupal,mambo,joomla and some other content management system. An example of drupal error is like this:
"Call to undefined function: user_access()"
To solve this, just put the following inside the php.ini under your public_html (If php.ini not available, create it)
session.save_handler = files
session.cache_limiter = nocache