Registration form error, Tooltip not displays,Event calendar doesn't to work after update ES2.1

Dear all,

after updating from ES Beta to ES 2.1.x I have trouble with registration form - while checking Username and/or permalink always an server Error occurred. Also the "tooltip" for messages, users, etc. will not be displayed correctly - message "Unable to load tooltip content." And event calendar will not displayed anymore - just a loading circle appears instead...

Need urgent assistance on this behavior because users could not register on site. Thank you!

Best regards
Andreas