I have issues with rewrite rules on an apache server.
RewriteRule ^(.)-f([0-9]) viewforum.php?f=$2&%{QUERY_STRING} [L]

I have disabled this rule in my config now. when enabled images links on server do not work (The forum you selected does not exist.)
I guess this rule would rewrite *any url as a viewforum parameter .
removing this rule makes sure it works, need to check if this rule would be required for any special case and if it would break anything?