everyone seems to be having a problem with it so I see a lot of people rolling back because 1.1.5 is utterly useless.
1.1.4 had quite a few bugs. 1.1.5 is much more aligned with the JSF specification. The bugs that people are having with 1.1.5 are usually are due to them relying on bugs in the 1.1.4 implementation that have been fixed. Therefore, the problem isn't with 1.1.5, but with peoples code (code that used to work in 1.1.4 shouldn't have). I have been using 1.1.5 for a while now with a lot of code on top of it, and although I did have to tweak some of our code, the upgrade from 1.1.4 to 1.1.5 wasn't that hard (mostly our problems were due to the select items change). As for your problem:
From your stack, the component that is getting the error does NOT have
an ID assigned. That is why I asked you to provide the XHTML code that is failing. Please stop bashing myfaces without good specific issues. You will find that no one will want to help you if this continues. Also please, when someone asks you to provide more information, do so. We are trying to help you out, but without your cooperation we cannot. We don't have your code and it is often hard to troubleshoot someone else's issues through a mailing list.

