In latest YAF 2.2.4 version, click on "Quick Reply" below any forum post and then click on "Post" button.
Here is the server error
No mapping exists from object type YAF.Core.YafContext to a known managed provider native type.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentException: No mapping exists from object type YAF.Core.YafContext to a known managed provider native type.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.