What i want:

• Force www [works]
• Restrict access to .inc.php [works]
• Force redirection of abc.php to /abc/
• Removal of extension from url
• Add a trailing slash if needed

old .htaccess :

    Options +FollowSymLinks


    <IfModule mod_rewrite.c>

    RewriteEngine On
    RewriteBase /

    ### Force www
    RewriteCond %{HTTP_HOST} ^example\.net$
    RewriteRule ^(.*)$ http://www\.example\.net/$1 [L,R=301]


    ### Restrict access
    RewriteCond %{REQUEST_URI} ^/(.*)\.inc\.php$ [NC]
    RewriteRule .* - [F,L]


    #### Remove extension:
    RewriteRule ^(.*)/$ /$1.php [L,R=301]



    ######### Trailing slash:
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_URI} !(.*)/$
    RewriteRule ^(.*)$ http://www.example.net/$1/ [R=301,L]
    </IfModule>

New .htaccess:

     Options +FollowSymLinks


     <IfModule mod_rewrite.c>

    RewriteEngine On
    RewriteBase /

    ### Force www
    RewriteCond %{HTTP_HOST} ^example\.net$
    RewriteRule ^(.*)$ http://www\.example\.net/$1 [L,R=301]


    ### Restrict access
    RewriteCond %{REQUEST_URI} ^/(.*)\.inc\.php$ [NC]
    RewriteRule .* - [F,L]


    #### Remove extension:
    RewriteCond %{REQUEST_FILENAME} \.php$
    RewriteCond %{REQUEST_FILENAME} -f
    RewriteRule (.*)\.php$ /$1/ [L,R=301]

    #### Map pseudo-directory to PHP file
    RewriteCond %{REQUEST_FILENAME}\.php -f
    RewriteRule (.*) /$1.php [L]

    ######### Trailing slash:
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteCond %{REQUEST_FILENAME} !/$
    RewriteRule (.*) $1/ [L,R=301]

    </IfModule>

errorlog:

     Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: http://www.example.net/

Rewrite.log: http://pastebin.com/x5PKeJHB