I have installed xoops, and i have the following page:
http://prague.servershost.net/~sample/html/

I log in properly (although when i enter the username and password i get a page

Incorrect Login!
If the page does not automatically reload, please click here

if i wait for a while i do get in.

Then i press "Administration menu" and i get a page

This is your first time to enter the administration section. Press the button below to proceed.

i pressed the button a lot of times but a new page opens writting :

failed open file
Logging you in..

If the page does not automatically reload, please click here


and returns me to the previous page

what can i do?

andy

It may have to do with the fact that you seemed to have configured your mainfile to http://66.225.237.216/~sample/html/
and you are trying to access through
http://prague.servershost.net/~sample/html/

Make both the same (mainfile.php)

Also check https://xoops.org/modules/newbb/viewtopic.php?topic_id=27290&forum=27&post_id=118754
https://xoops.org/modules/newbb/viewtopic.php?topic_id=25834&forum=7&post_id=115725

Also check that your software firewall (if any) is not blocking the HTTP_REFERER (a.k.a. "Information about visited sites" in advanced privacy settings in Norton) for this site - this can usually be configured on a per-site basis in your software firewall configuration.