Problem with swiftriver installation


I am new to swiftriver and ushahidi.
I downloaded swiftriver from git-hub ,and tried to install in my local system(ubuntu+xampp).
when ever i tried to access swiftriver it shows the following errors

*Fatal error: Call to a member function add() on a non-object in /opt/lampp/htdocs/SwiftRiver/application/classes/Kohana/Exception.php on line 28
please help


I have the very same problem. Any support would be much appreciated. Thank you!