[xwiki-users] help

Dear Mr/Mrs, I am a newcomer to this group and beginner to study xwiki. Now I have deployed a xwiki.war package in Tomcat Container with Mysql as the rlational dabase. After I finished figuration XWiki, I wanted to import the default Wiki that http://www.xwiki.org is providing as a XAR file. But I can't upload a new package, every time I selected the XAR file and clicked the UPLOAD icon, the screen returned to the page before I selected and clicked. I don't know what to do to solve this problem, and I hope someone can give me some advices. Thank you so much for your time! I am looking forward to your reply. Respectively yours, Shayne