"The WinRM client cannot process the request. It cannot determine the content type of the HTTP response from the destination computer. The content type is absent or invalid."
The EMC was giving a kerberos error. I couldn't copy and paste it into anything and could only click retry, so I don't have the error because I didn't write it down.
After reinstalling the WinRM IIS thing about 10 times and running quickconfig (qc, not all typed out) and going through every single setting in IIS and comparing the broken DAG machine with the working DAG machine I was stuck. (And I'm sure you know exactly what I'm talking about because it's always the same answers to the same thing that never works but you try it 3 or 4 times because you don't know what else to do but you have to do something so...)
This blog pointed me in the right direction:
http://trikks.wordpress.com/2012/08/13/exchange-error-of-death-the-winrm-client-cannot-process-the-request-it-cannot-determine-the-content-type-of-the-http-response-from-the-destination-computer/
As it turns out the following file had errors in it:
E:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\PowerShell\web.config
On the server that was broken there were multiple entries with a path like the following:
<codebase href="file:///%ExchangeInstallDir%bin\Microsoft.Exchange.Configuration.RedirectionModule.dll" version="14.0.0.0">
On my good server it had the same line as:
<codebase href="file:///E:\Program Files\Microsoft\Exchange Server\V14\bin\Microsoft.Exchange.Configuration.RedirectionModule.dll" version="14.0.0.0">
I renamed the broken web.config file and copied over the working one from my other box and everything just worked from that point.
This tool was no help to me on this error (probably because Exchange powershell was broken?):
http://blogs.technet.com/b/exchange/archive/2010/12/07/3411644.aspx
I hope this helps someone.
{edit - corrected typo in a sentence}
