Domain routing possibilities in CI?

[eluser]lonka[/eluser]
Unfortunately I have got 500 Internal Error again
When I delete line with

Code:

RewriteCond %{HTTP_HOST} ^((?!www\.)[^\.]+)\.

error 500 is gone.
I try to change rule to

Code:

RewriteCond %{HTTP_HOST} ^((?!www\.)[^\.]+)\.$

but this is no working as we are expecting