Error 500

Undefined variable: model
Application Log
Timestamp Level Category Message
10:26:06.083125 error php
Undefined variable: model
(/home/arshadspo/public_html/protected/controllers/ProductController.php:17)
Stack trace:
#0 /home/arshadspo/yii/web/CController.php(286):
ProductController->runAction()
#1 /home/arshadspo/yii/web/CController.php(265):
ProductController->runActionWithFilters()
#2 /home/arshadspo/yii/web/CWebApplication.php(282):
ProductController->run()
#3 /home/arshadspo/yii/web/CWebApplication.php(141):
CWebApplication->runController()
#4 /home/arshadspo/yii/base/CApplication.php(180):
CWebApplication->processRequest()
#5 /home/arshadspo/public_html/index.php(13): CWebApplication->run()
REQUEST_URI=/sports-wears/track-suits/track-suits-6.html