Problem with date in Boonex Events

I can't add a event with the Boonex Event module.
If i want to add a event, i get a error that the date is not correct.
( i also have no date picker when i click on start / end date --> on the rest of the site the date picker works good )

Does anybody knows how to solve this?

Does someone know?

What browser are you using? Moxilla Firefox works best for me, IE does not work well at all!

For testing we use Firefox, Chrome, IE, Safari and Maxthon 3...

Check this post for more info: http://www.boonex.com/forums/#topic/Datepicker-Fix-for-Firefox-19-and-Chrome.htm 

It's for 7.0.9 and only for the events datepicker. On all the other places it works good...

Does anybody know and can help me with it?