debug a php for my joomla

I have installed joomla on my domain and i cant get it to work. Other modules work fine but when i click on "add new article" i get the following error: Fatal error: Call to a member function getKeyName() on a non-object in .../libraries/joomla/application/component/[login to view URL] on line 801. I need this fixed ASAP so that i can continue with the work. You will just tell me what to edit in the PHP as i will not give you login for my domain. Lowest bidder who can do the job will be awarded. This shouldn't take you more than an hour so the hourly rate you build should be the full amount i will pay you.