AUSST - Update Server issue: IIS7 406 errors, and ERROR: Invalid webfeed

I spent today configuring and installing an instance of the AUSST2.0 software, following http://www.adobe.com/content/dam/Adobe/en/devnet/creativesuite/pdfs/Up dateServerSetupTool_TechNote.pdf 

Here's where I am:

Via Firefox/IE I get the following when browsing to the Updaterfeed.xml:

XML Parsing Error: syntax error

Location: <SERVER LOCATION>

Line Number 1, Column 1:

0001

^

Which I expect is ok...  the server is sending the updaterfeed.xml. I can also download the updates directly through IE or Firefox.  The corresponding entry in the IIS log is:

/AdobeUpdate/webfeed/oobe/aam20/win/updaterfeed.xml - 80 - <MY IP ADDRESS> Mozilla/5.0+(Windows+NT+6.1;+WOW64;+rv:9.0.1)+Gecko/20100101+Firefox/ 9.0.1 304 0 0 196

When I attempt to do an update via Photoshop, I receive:

"The update server is not responding.  The server might be offline temporarily, or the internet or firewall settings may be incorrect.  Please try again later.  Error Code: U41M1C213 "

This happens regardless of firewall status locally or on the server.  Other communication to the server is fine.

the aamu.log on level 10 says:

2012-01-17T20:01:52: Entering slurpURL: (http://<SERVER IP>/AdobeUpdate/webfeed/oobe/aam20/win/updaterfeed.xml) bytesPushed

2012-01-17T20:01:52: main download loop - waiting for network availability

2012-01-17T20:01:52: have network connection

2012-01-17T20:01:52: connected to: = http://<SERVER IP>/AdobeUpdate/webfeed/oobe/aam20/win/updaterfeed.xml

2012-01-17T20:01:52: received status code from server

2012-01-17T20:01:52: slurpURL: (http://<SERVER IP>/AdobeUpdate/webfeed/oobe/aam20/win/updaterfeed.xml) bytesPushed = 0

2012-01-17T20:01:52: CFU(Webfeed): dumping webfeed: C:\Users\<MY USERID>\AppData\Local\Adobe\AAMUpdater\1.0\Data\webfeed.xml

2012-01-17T20:01:52: CFU(Webfeed): ERROR: Invalid webfeed. Could not read webfeed sequence number.

2012-01-17T20:01:52: UCGetprogress : (B) Returning with value = 1

2012-01-17T20:01:52: UCGetprogress : Check for updates returning state for reffId  =

2012-01-17T20:01:52: UCGetprogress : Check for updates returning state     = 41

2012-01-17T20:01:52: UCGetprogress : Check for updates returning outError  = 213

2012-01-17T20:01:52: UCGetprogress : Check for updates returning percent   = 0

2012-01-17T20:01:52: UCGetprogress : Check for updates returning unique error code string   = U41M1C213

2012-01-17T20:01:52: UCGetprogress : (D) Returning with value = 1

2012-01-17T20:01:52: Stepped into << UCGetUserPreferences >> call.

2012-01-17T20:01:52: Returning from << UCGetUserPreferences >> call with return value -  = 1

The subsequent IIS Log entry for this is:

GET /AdobeUpdate/webfeed/oobe/aam20/win/updaterfeed.xml - 80 - <MY IP ADDRESS> AAM+Updater+1.0 406 0 0 19

I've added the <add name=”SSINC-xml” path=”*.xml” verb=”*” modules=”ServerSideIncludeModule” resourceType=”Unspecified”> to my web.config, per http://blogs.adobe.com/oobe/2010/09/enterprise-in-house-update-hosting -for-cs5.html

I continue to get the U41M1C213 error whilst updating.  I can get the updates when I remove the AdobeUpdater.Overrides from C:\ProgramData\Adobe\AAMUpdater\1.0 (Win7)

Help?