After creating a node in activity module I am getting an error "undefined index"
Have a look at the issue queue for Activity.

In particular: Causes undefined index _node_query_node_access_alter


  Not sure why activity would be a culprit of this, but non admin users
  see this error when viewing default activity view or any other
  acitivity views created. This error will also occur on a page when the
  view is a block.
  
  Notice: Undefined index: table in _node_query_node_access_alter()
  (line 3197 of /var/sites/my/modules/node/node.module).