After installing InstantForum.NET 2012 I receive the following error when composing topics or replies within the rich text editor. 

Exception type: InvalidOperationException

Exception message: Request format is unrecognized for URL unexpectedly ending in '/ParseForPreview'.

Resolution

To resolve this problem please follow the steps below…

1. Open your InstantForum.NET 2012 web.config file within NotePad or similar.

2. Add the entire  <webServices> element as shown inside the <System.Web> element.

<system.web>

 <webServices>
   <protocols>
       <add name="HttpGet"/>
       <add name="HttpPost"/>
   </protocols>
</webServices>
3. Save and replace your web.config. 

That's It!. 

These steps should resolve this exception. If the problem continues of course please don't hesitate to open a support ticket or contact us.