You can use the default one as long as you edit it for 3rd party components.

1) How can I check if SEF Advance is installed and enabled for jReviews? With OpenSEF you do a check for _OPENSEF, is there a constant defined in SEF Advance that I can check? I need this for my xajax functionality because I have to manually include the SEF file if it is enabled to redirect to a sef url because the xajax bot is run before the sef one.

Originally sef_ext.php files were made for SEF Advance only because I invented the extension file standard. It was later adopted by other SEF components.
So if there are no defines it should work with SEF Advance. If it doesn't mail the component author.

2) I can't seem to get the new caching to work. The cache files are created but the number of queries remain the same (using the Joomla debug). I assume the cache is checked before running the create function, correct? What could be the problem? I am running this on a local server.

First time it would be the same number of queries until the URLs are cached. If you reload the page you will notice how the number of executed queries decrease.

Then it's pretty strange. Have you tried installing it from directory?

Please have some patience. I will have a look on it soon and let you know.

Regarding the dmain switch please send me an email and I will take care of that.

Regarding the articles could you make a search and see if the article is already in the database and edit it instead of adding another one with the same name?

/usr/lib/ is not within your shared directories under open_basedir
Either add /usr/lib/ there like:

/www/htdocs/v034163/:/tmp:/usr/bin:/www/htdocs/v034163:/bin:/usr/local/bin:/usr/share/php:/usr/lib

or move ioncube to some of the allowed paths like /usr/bin/ioncube/

Don't forget to restart Apache.

Could be something wrong with mod_rewrite. Try /administrator/index.php
Also post the content of your .htaccess file.

Looks like some server configuration / permission problem.
Is ionCube installed in php.ini? Is it dedicated server or hosted site?

Do you have safe_mode on?
Can you install other components?

If i disable the bridge i am getting this:

The page you are trying to access does not exist.
Please select a page from the main menu.

If you get this make sure the component has been added to main menu and it's public (not registered).

The available SEF Advance extensions that I know of are listed here:
http://www.sakic.net/products/sef_advance/extensions/

Don't know if Docman extension is available yet, if anybody finds it please post here.

You can change URLs to lower-case in SEF Advance configurations > Preferences Tab > Lower case > Yes

From what I can see in the attached jpg everything is fine. If aliases are not working I don't know what's wrong. I would have to take a look so it's best to send me your admin password and FTP access by mail.

You can change "remository" string in SEF Advance configuration under "Custom component strings", "components with SEF extension". Enter remository=>download

Yes, in that case the table view would need to have a string instead so they can be distinguished.
I could add this as an option for a future versions of SEF Advance. But I can't say when at this time.

Currently it's not possible but I will have a look on that for the next version.

then i have another problem, because "normal" aliases are working great, but what i have / want is:

contact
- impressum
- - datenschutz
- - nutzungsbedingungen
- ...

and therefore i need slashes in my url, is there another way to realize it?

What I meant is that it must be no slashes at the beginning or at the end of the URL. So you can have something like:

Non-SEF URL: index.php?option=com_content&task=view&id=4&Itemid=9
Alias: contact/impressum/datenschutz

I have two other questions, maybe you can help me there too:

1.) i use remository and have urls like this:
http://www.domain.de/remository/download/Bildbearbeitung.html
-> is it possible to remove the component name "remository" in the url?

No. You can change it to anything else though. But you can't remove it completely, unless you want to use aliases again.

2.) normally i use blog listing, not the table listing and the problem is that only in table listing the url is like domain.de/news/website and in blog view the url looks like domain.de/section/website...

That's right. When yo use bloglistings the URL will be:
http://www.domain.com/blogsection/section_name/
String "blogsection" can be changed to anything else.