If you are using non-ascii urls you may need to add a config setting because of changes in this release. See this document:
It sounds like maybe encoding the url made it too long and if it throws a path too long exception it may ban the ip because it seems like a malicious url.
What you can do is comment out the banned ip module from Web.config to disable the banned ip module. Then go into Administration > Advanced Tools Banned IP Address and delete your ip from the list.
Hope it helps,