I'm not sure how you are using TopLink within the app, if it is ADF that obtains the sessions or your application. The error and log though are quite explicit - you are logging out of the session and then trying to acquire a ClientSession from it which is not allowed. What needs to be determined is why or how you are logging out while the application is still running.
I have seen unintentional logouts occur if there are different classloaders involved. Some of the SessionManager's getSession methods have one that takes a classloader with the intent of loging out and logging back in a session if the classloader is different from the one the singleton has a reference to - which is useful if the app is redeployed. This can be a problem though if you have multiple sessions with the same name, since the apps using them might have different classloaders. Check that you don't have multiple apps all accessing the 'default' session - if you do, try giving each app's session a unique name.