I have the same exact problem , below is what i saw in errors_log when i was just sitting idle at the services page, then bam it displayed No matching services found showing 1 out of 180 records however nothing just blank.
[Wed Sep 15 14:33:03 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: Entity: line 1933: parser error : PCDATA invalid Char value 8 in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:03 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: (3240) MOD:(3360) MOD:(3360) MOD:(3240) MOD:(3000) Redundancy:(Fully Redundant) in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:03 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: ^ in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:03 2010] [error] [client 10.10.10.2] PHP Warning: Invalid argument supplied for foreach() in /usr/local/nagiosxi/html/includes/components/xicore/ajaxhelpers-servicestatus.inc.php on line 354, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:09 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: Entity: line 1933: parser error : PCDATA invalid Char value 8 in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:09 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: (3240) MOD:(3360) MOD:(3360) MOD:(3240) MOD:(3000) Redundancy:(Fully Redundant) in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:09 2010] [error] [client 10.10.10.2] PHP Warning: simplexml_load_string() [<a href='function.simplexml-load-string'>function.simplexml-load-string</a>]: ^ in /usr/local/nagiosxi/html/includes/utils-status.inc.php on line 21, referer:
http://localhost:9000/nagiosxi/includes ... w=services
[Wed Sep 15 14:33:09 2010] [error] [client 10.10.10.2] PHP Warning: Invalid argument supplied for foreach() in /usr/local/nagiosxi/html/includes/components/xicore/ajaxhelpers-servicestatus.inc.php on line 354, referer:
http://localhost:9000/nagiosxi/includes ... w=services