was reproduced on two computers. Start clean liferay + tomcat bundle, configure it to use mysql.
After starting and logging in as admin go to Control Panel -> Sites and try to create any site (Blank Site or any site-template based site)
Enter site name and press "Save". Error message "Your request faled to complete is displayed (log is empty).
BTW - site is created. but, in case we are using site-template no any pages are populated