500 Internal Server Error

preg_replace(): Unknown modifier '\' (2)

#0 [internal function]: flight\Engine->handleError(2, 'preg_replace():...', '/home/noslang/i...', 417, Array)
#1 /home/noslang/includes/func.inc.php(417): preg_replace('/\\bw/\\b/i', 'W/', 'The acronym w/ ...')
#2 /home/noslang/templates/pages/searchresults.php(101): UppercaseSlang('w/', 'The acronym w/ ...')
#3 /home/noslang/flight/template/View.php(118): include('/home/noslang/t...')
#4 /home/noslang/flight/template/View.php(131): flight\template\View->render('/pages/searchre...', Array)
#5 /home/noslang/flight/Engine.php(432): flight\template\View->fetch('/pages/searchre...', Array)
#6 /home/noslang/flight/core/Dispatcher.php(203): flight\Engine->_render('/pages/searchre...', Array, 'template_conten...')
#7 /home/noslang/flight/core/Dispatcher.php(142): flight\core\Dispatcher::invokeMethod(Array, Array)
#8 /home/noslang/flight/core/Dispatcher.php(48): flight\core\Dispatcher::execute(Array, Array)
#9 /home/noslang/flight/Engine.php(63): flight\core\Dispatcher->run('render', Array)
#10 /home/noslang/flight/core/Dispatcher.php(203): flight\Engine->__call('render', Array)
#11 /home/noslang/flight/Flight.php(43): flight\core\Dispatcher::invokeMethod(Array, Array)
#12 /home/noslang/public_html/index.php(621): Flight::__callStatic('render', Array)
#13 /home/noslang/flight/core/Dispatcher.php(164): {closure}('%w/%', Object(flight\net\Route))
#14 /home/noslang/flight/core/Dispatcher.php(143): flight\core\Dispatcher::callFunction(Object(Closure), Array)
#15 /home/noslang/flight/Engine.php(309): flight\core\Dispatcher::execute(Object(Closure), Array)
#16 /home/noslang/flight/core/Dispatcher.php(191): flight\Engine->_start()
#17 /home/noslang/flight/core/Dispatcher.php(142): flight\core\Dispatcher::invokeMethod(Array, Array)
#18 /home/noslang/flight/core/Dispatcher.php(48): flight\core\Dispatcher::execute(Array, Array)
#19 /home/noslang/flight/Engine.php(63): flight\core\Dispatcher->run('start', Array)
#20 /home/noslang/flight/core/Dispatcher.php(191): flight\Engine->__call('start', Array)
#21 /home/noslang/flight/Flight.php(43): flight\core\Dispatcher::invokeMethod(Array, Array)
#22 /home/noslang/public_html/index.php(1063): Flight::__callStatic('start', Array)
#23 {main}