Changing documentroot in Apache on Linux (Ubuntu)

[visualAd]

Naah, maybe it's sth else...
I tried all the above, only "chmod -R u=rwX, g=rX, o=rX" I did not try as I dont know what user or group should be used.
Eventually got all them excecute without errors, but no effect when I go to localhost.
Still get the dreaded:

Have you got an index page in there? I.e. index.html? If not and, if you have not enabled directory listings you will get a forbidden error.

To enable directory listings:

<Directory /path/to/document/root>
    Options +Indexes
</Directory>