During my administrator page of joomla, after i use of module, this error is made an appearance.

My version: Joomla! 1.5.23

Please, assist me to.

You need to then add particulars for your answer, for example wich version of Joomla! you are running, and when this error happened after installing some module or under other circustamces.

By the feel of that, I'd say there is something wrong within the XML "manifest" of the module try looking in the modules/ directory, find each module xml if the xml is malformed or incomplete or something like that not right.

If the happened once you installed a module, try crippling it via database (within the __modules table, while you cannot access the AP obviously) and getting rid of it and find out if the solves the problem.