Can't login to admin

[Paradox]

Suddenly broke access to the admin panel. I enter my username / password - opens without a single white sheet of labels.

This log errors CMS repeats the following entry:

[25-Apr-2014 09:00:14] PHP Warning: SimpleXMLElement::__construct() [<a href='simplexmlelement.--construct'>simplexmlelement.--construct</a>]: Entity: line 9: parser error : Extra content at the end of the document in /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php on line 44
[25-Apr-2014 09:00:14] PHP Warning: SimpleXMLElement::__construct() [<a href='simplexmlelement.--construct'>simplexmlelement.--construct</a>]: n&gt;&lt;![CDATA[Invalid User]]&gt;&lt;/Reason&gt;&lt;/entry&gt;&lt;/channel&gt; in /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php on line 44
[25-Apr-2014 09:00:14] PHP Warning: SimpleXMLElement::__construct() [<a href='simplexmlelement.--construct'>simplexmlelement.--construct</a>]: ^ in /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php on line 44
[25-Apr-2014 09:00:14] PHP Fatal error: Uncaught exception 'Exception' with message 'String could not be parsed as XML' in /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php:44
Stack trace:
#0 /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php(44): SimpleXMLElement->__construct('<?xml version="...')
#1 /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/login_functions.php(36): GS_Logging_Class->__construct('failedlogins.lo...')
#2 /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/common.php(250): include_once('/var/www/parado...')
#3 /var/www/paradox2/data/www/bonus-poker.ru/admin/index.php(14): include('/var/www/parado...')
#4 {main}
thrown in /var/www/paradox2/data/www/bonus-poker.ru/admin/inc/logging.class.php on line 44

Any changes or installations of new modules have been conducted. Yesterday admin panel worked today - no longer exists.

[Paradox]

Rolled the server to the previous restore point and the problem went away.

[shawn_a]

Your failurelog was corrupted
What version of GS are you using, cryllic username causes it, which was recently fixed.