Symptoms

If you ever get the following error message when developing a Custom K2 application using 4.6.9:

"Please ensure that the needed configuration node(s) are configured in your configuration file... Please refer to the help documentation for further details."

Diagnoses

This is due to a configuration change that was implemented in K2 blackpearl 4.6.9 wherein a number of configurations were consolidated into a single configuration file a.k.a the K2HostServer.exe.config file.
You can find more information in the following KB Article: http://help.k2.com/kb001637
 

Resolution

The configuration change is documented in the following KB: http://help.k2.com/kb001637