[Scan Cape Cod]

Usually I don't have many problems with these add-ons but this one's giving me some grief. I've followed the instructions to the letter, but when I try to access the Wiki I receive this:

Detected bug in an extension! Hook UserLoadFromSessionHook failed to return a value; should return true to continue hook processing or false to abort.

Backtrace:

#0 /home/scott2/public_html/wiki/includes/User.php(810): wfRunHooks()
#1 /home/scott2/public_html/wiki/includes/User.php(260): User->loadFromSession('UserLoadFromSes...', Array)
#2 /home/scott2/public_html/wiki/includes/User.php(1870): User->load()
#3 /home/scott2/public_html/wiki/includes/StubObject.php(58): User->getOption()
#4 /home/scott2/public_html/wiki/includes/StubObject.php(184): StubObject->_call('nocache')
#5 [internal function]: StubUser->__call(Array, Array)
#6 /home/scott2/public_html/wiki/includes/OutputPage.php(180): StubUser->getOption('getOption', Array)
#7 /home/scott2/public_html/wiki/includes/Article.php(748): OutputPage->checkLastModified('getOption', Array)
#8 /home/scott2/public_html/wiki/includes/Wiki.php(450): Article->view('nocache')
#9 /home/scott2/public_html/wiki/includes/Wiki.php(63): MediaWiki->performAction('20100216214239')
#10 /home/scott2/public_html/wiki/index.php(116): MediaWiki->initialize()
#11 {main}

I tried searching this thread for a solution. All that looked relevant was having CSS Stylesheets saved as files, which I do not. I'm running 4.0.2 PL1 and Mediawiki 1.15.1.

Thanks in advance!