First, can you see the said /install/test/index.html file on your server (using FTP for example?)

No matter what you can continue installation and then manually replace your old .htaccess with the provided sample.htaccess in your b2evolution root folder.

Yes, the text in that said file is:

"Test successful.

If this page can be loaded, it means that the .htaccess that is being staged in this test folder
did *NOT* crash apache. This is good. This means we can use that .htaccess file in production."

If I rename sample.htaccess to .htaccess (in blogs/..... ) I do get the following respons when opening the website:

"Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@la2yg.net and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.
Apache/2 Server at la2yg.net Port 80"

This msg is from my own freshly installed websige (ver 6.4.4.1) but I get the same respons from the "old" la1g.com with ver 6.6.1

ok, so I think that message pretty clearly tells you who you need to talk to to get it fixed.

Thank you for guidance.
As you can understand my knowledge of DB are next to nothing.
Cliche webhotel suggested to comment out "Options -Indexes" which made it for la2yg.net with ver 644 but on la1g.com with ver 661 I had to also comment out "AcceptPathInfo" in .htaccess file.
But still I do get a warning about DB misconfiguration. so I need to talk a litle more with Cliche.

Edit:
OK, so I now had: Cliche does not support InnoDB !

Exept from a new provider, any suggestion?

There's 3 things there they don't support!

You really need to a **real** webhosting plan!

Ok, problem with .htaccess solved!
New host provider, the DB-problem most likely solved.
Thanks and have a good weekend