If you read the Forums Charter, you will find a rule telling you to use "example.com" for all examples. There are several reasons for the rule. In the Apache forum, the important reason is: example.com (or .net or .org) is not auto-converted into a clickable link. We need to see what you typed, not go to the site.
I set the flag to [L] to stop apache to not execute the next rule( add 3w in the begining of the url) if he finds the excluded keywords in the url.
Yes, that's what I thought. But if your only reason for the [L] is to prevent certain URLs from reaching the www redirect, then the rules should be expressed as
RewriteRule (exception|otherexception|thirdexception) - [L]
meaning "don't do anything, just stop mod_rewrite here".
Next problem: your Rules as written have / at the end. This means they may or may not work for directories, depending on whether mod_dir has already executed. (If it has, then any request for a directory will reach mod_rewrite with "index.html" at the end.) And it will never work for files.
Are your exceptions all directory names, or are some of them filenames? If some of the exceptions are filenames, do they have extensions?
Is there any place where an excepted name could be
contained within a non-excepted name? For example: You want to make an exception for /foo/ or /foo.html but not for /foobar/ or /oldfoo.html. Then you have to write the rule and/or conditions very carefully. If you are certain this will never happen, you can -- ahem!-- cheat by ignoring the possibility.
But I need some pages to be reached with 3w and also without 3w.
I am surprised g1 has not said something about this ;)
Why do you want certain pages to have more than one URL? Redirecting in htaccess will not prevent the pages from being reached. Pick one form -- either with or without www -- and use it everywhere.