After installing ubercart and all the required modules I get the error about node access on line 3087 of /node/node.module.When I check the home page as annomoyous user. The error is only on the home page I have tried to modify ReWriteBase but it took me off line.Im running apache2 on a linux mint13 box with drupal 7.22. At first I wasn't able to get clean urls but I think I am able now. but still get the error Notice: Trying to get property of non-object in node_node_access() (line 3087 of /drupal-7.22/modules/node/node.module). Please help me find a solution