Google Checkout Session Issue

[getopt]

Hello ,i got a problem about session something ,when I add product to my shopping cart ,and click googlecheckout button ,it redirect me to google checkout page ,correct ? without signing in ,i try to edit my order ,then it send me back to my shopping cart ,everything seem Ok right here ,then I click google checkout again ,and in googlecheckout page ,I sign in with my google username ,and password ,I click Edit my Order ,it still send me back to my shopping cart ,but everything is gone ,I mean my shopping cart 's empty , look like it automatically clear the session . Anybody got this problem before ,or any experience about this ,any help will be most appreciated.Thank you so much