Can't find master page `'.html_document.'` !

File: /home/vol15_3/host site/hzree_19470014/mysite/htdocs/ow_core/theme_manager.php

Line: 220

Trace:

#0 /home/vol15_3/host/hzree_19470014/my site/htdocs/ow_core/html_document.php(610): OW_ThemeManager->getMasterPageTemplate('html_document') #1 /home/vol15_3/host/hzree_19470014/my site/htdocs/ow_core/response.php(171): OW_HtmlDocument->render() #2 /home/vol15_3/host/hzree_19470014/my site/htdocs/ow_core/application.php(469): OW_Response->respond() #3 /home/vol15_3/host/hzree_19470014/my site/htdocs/index.php(94): OW_Application->returnResponse() #4 {main}

Type: InvalidArgumentException

I keep get that message anytime i try to log into the admin pagr why?

Please i need help