unable to start debugging on the web server an authentication error occured while communicating with the server - VS2008 + IIS5.1

Question

It seems lots of people are having the same problem, but with different error messages.

the error message I get is...

"unable to start debugging on the web server an authentication error occured while communicating with the server"

there is a great link from MS detailing every other debugging error message except my one - http://msdn.microsoft.com/en-us/library/Aa290100

Here at work were forced to use XP and IIS 5.1 :(

I have been working on an SVN branch for around a month and set up VS 2008 to work with IIS 5.1 and all was well, as soon as i started debugging everything was fine.

after merging my code back to the trunk, my cproj files started complaining that the virtual folder for IIS was not found and this disabled the project.

To resolve this I deleted XML right at the bottom of the Cproj file

  <ProjectExtensions>
<VisualStudio>
  <FlavorProperties GUID="{349c5851-65df-11da-9384-00065b846f21}">
    <WebProjectProperties>
      <UseIIS>True</UseIIS>
      <AutoAssignPort>False</AutoAssignPort>
      <DevelopmentServerPort>2178</DevelopmentServerPort>
      <DevelopmentServerVPath>/</DevelopmentServerVPath>
      <IISUrl>http://localhost.dev&lt;/IISUrl&gt;
      <NTLMAuthentication>False</NTLMAuthentication>
      <SaveServerSettingsInUserFile>False</SaveServerSettingsInUserFile>
    </WebProjectProperties>
  </FlavorProperties>
</VisualStudio>

After that I could start the project, but after trying to set IIS 5.1 up with VS 2008 I get the above error.

the annoying this is that I can debug by manually attaching it, but that’s just tedious.

ive read many post saying to change registry values etc, but I shouldn’t need to do that as I was working. + ive made sure http keep alives is enabled and integrated windows authentication is ticked.

This is truly an annoying error, does anyone have a solid solution ??

Any help is most appreciated

Truegilly