In my administrator page of joomla, when I access to module, this error is appeared.
My version: Joomla! 1.5.23
Pls, help me.
You should add some details to your answer, such as wich version of Joomla! you're running, and if this error happened after the installation of some module or under other circustamces.
By the look of that, I'd say there's something wrong in the XML "manifest" of a module; look in the modules/ directory, find each module xml and see if the xml is malformed or incomplete or something not right.
If this happened after you installed a module, try disabling it via database (in the __modules table, as you cannot access the AP of course) and removing it and see if this solves the issue.