Hi there. For all of you with errors after install. I had a similar issue and it was quite easy to correct.
When you logon the index.php page is not opened, I see a directory listing. The POST from has the action set to ./ (no file name), this i why the data gets sent to the directory instead of index.php (and logon).
I had to either fix the action to index.php or edit my .htaccess and add
DirectoryIndex index.php in the root.