You will see an error message similar to:
Unable to loadresource:http://188.8.131.52:5050/AM8PROD/classes/AttachLayout_signed.jar
To resolve the issue please shut the instance down then run awinstall. Please confirm everything then when it comes to the menu choose options...
02 Reapply portions of the upgrade
07 Reset JNLP files
Let this run through then quit out. Please then clear the java cache for this client machine and then try and access the instance.