<cite>wangwei22: </cite> I'v found the reason, my cookie is polluted, everything goes well after I clear the cookies.
Thanks for your useful answer!
The local sample succeed finally after my effort!However,the sample "Taskever" system is still running wrong!
I opened the url <a class="postlink" href="http://www.taskever.com/,and">http://www.taskever.com/,and</a> I wanna register an account.But there is an error when I clicked the "Register" button.It said "An internal error occured during your request!".At the same time,I downloaded the source code,then everyting was ready!And I successfully registered an account,the system required me to active my mail,but I only modified the field "IsEmailConfirmed" of "AbpUsers" table as true,nothing else.But when I logined in the system with my new account,it occurred an error that "AbpRoles is invalid".Pls help! :( :( :(