[xwiki-users] Blog.CreatePost forwarded to wrong url

Hi, all, I got a weired problem with url handling, when I am on this page: http://mydomain.com/xwikim/bin/view/Blog/CreatePost, which gives me a create post button to create post, I check the form action url is: "/xwikim/bin/view/Blog/CreatePost?xpage=plain", when I click on the create button, it comes to this url: http://localhost/xwikim/bin/edit/Blog/Post+title?template=Blog.BlogPostTemp…JaWpElmFlAzjoSKw, from which I got "Unable to connect" error, I am not sure why it switched from mydomain.com to localhost, all other links and buttons are working fine without this kind of problem. My setup is like that I have an apache web server installed with port 80 opened to the public internet, which forwards request to tomcat with port 8082 on localhost. all other links work fine, only the createpost has this problem. Any clue from any of you? Thanks very much in advance Dave