I faced the issue above when I upgraded from Sitecore 8.1 update 3 to Sitecore 8.2 update 1.
I only got this exception where I use configuration factory for pipeline because of Dependency Injection. Like the following:
Then I got the exception “No group node for sub node: httpRequestBegin”. After I digged into the new Sitecore.Kernel I found that Sitecore wants a group ancestor for the processor. That did not really help me because if I put the group node above a processor then Sitecore does not know that it is a processor.
So I deciced to report this is a bug and they provided me an answer that they will provide a hotfix package for this issue. The reference number is 142817.
UPDATE:
We got the hotfix from Sitecore support. They had to do changes in Sitecore.Kernel assembly. The fix is only working for Sitecore 8.2 update 1 that’s why I don’t want to share here. Good news that they are going to include this fix in Sitecore 8.2 update 3.
