Bug: Class 'Controller' not found

hi, i am a YII newbie, found this bug when i am learning YII:

php ENV: under xamp1.7.4(php5.3.1) or Zwamp(php5.3.3)

YII: 1.1.9

trigger case:

step1 - run "php.exe yiic webapp test1", result "ok"

step2 - try to access on browser, result "ok"

step3 - run "php.exe shell", result "ok", but there is a new file "Controller.php" is created under test1/, and its content is empty!!

step4 - try to access on browser or run other commands, result "nok"

“Fatal error: Class ‘Controller’ not found in path\test1\protected\controllers\SiteController.php on line 4”

if remove "Controller.php", then the app revert, i think it should be a bug…