New-SplunkIndex fails with 400 status / Argument "search" is not supported by this handler.

[halr9000]

Answers post: http://answers.splunk.com/answers/216632/new-splunkindex-400-response-code.html

Root cause is that the Invoke-HTTPPost function is incorrectly embedding a search parameter into the REST call, as shown here:

Run cmdlet with verbose:

 <response>
   <messages>
    <msg type="ERROR">
  In handler 'indexes': Argument "search" is not supported by this handler.</msg>
   </messages>
 </response>

Digging into the verbose output, we can see the data being POST'ed to the Splunk endpoint:

VERBOSE:  [Invoke-HTTPPost] :: $PostString = search=&name=test