Panels Wizard does not work when clicking the save button

I've tried the following:

• go to a wiki on the xwiki farm
• set the news skin
• import the panels (the version on http://www.xwiki.org/xwiki/bin/view/Code/PanelsApplication)
• go the wizard page, select the menu on the left, pick a panel
• click on save.

I'm attaching a screenshot of the error