I too have had the exact same issue, but I thought I would follow up with my actual fix, as searching for "U41M1C213" through google constantly yielded this post, along with your others.
After digging through the blog replies on this thread > http://blogs.adobe.com/oobe/2010/09/enterprise-in-house-update-hosting-for-cs5.html < i did find the answer from both Christopher Kinard and Travis Henry which ultimately fixed this error.
I'll walk through the general setup
- I followed this guide for the initial AUSST2.0 sync + IIS7 site setup: http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/creativesuite/pdfs/Ad obeApplicationManagerEnterpriseEditionDeploymentGuide_v2_1.pdf
- Then as per the folks advice that I credited above, suppliment what the above deployment guide says and add server side includes for all the file types that you are putting in for IsapiModule handlers (zip, xml, crl, dmg, and sig). I added them through the IIS Manager GUI, as opposed to manually entering them into the web.config file. See screenshot of the end result of all added handler mappings, and an example entry below:
Hope this helps anybody that might be battling with this, as it does not appear to be very well documented.
Yes, finally, thank you!