Thread:Project:Support desk/Internal Error - PEAR mail package is not installed/reply (4)

That's really odd. You said that check_php.php from the web shows include_path .:/usr/share/php, so adding it to ini_set in LocalSettings.php shouldn't be necessary, since it should be there already.

Maybe try a var_dump(ini_get('include_path')); in LocalSettings.php to see if it's really there