After a few hair lost... BlogEngine is finally running on the production server...

IIS6... not 7, so i had to install the asp.net MVC,
http://www.microsoft.com/downloads/details.aspx?FamilyID=c9ba1fe1-3ba8-439a-9e21-def90a8615a9&displaylang=en

and then added a wildcard mapping to have IIS pass all requests to asp.net
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/5c5ae5e0-f4f9-44b0-a743-f4c3a5ff68ec.mspx?mfr=true

1. In IIS 6, go to the Application Configuration Properties for your ASP.NET MVC web application.
2. Click "Insert..." in the Wildcard application maps section.
3. Set the Executable to the path of the aspnet_isapi.dll (on my machine this is c:\windows\microsoft.net\framework\v2.0.50727\aspnet_isapi.dll).
4. Make sure NOT to check the "Verify that file exists" and click "OK".

After all of this, the Blog was still crashing...

Even after disabling the Custom Errors in the web.config
<customErrors mode="Off" />

I still did get the nice oops error message of BlogEngine.

I tried the trick to disallow inheritance for the whole system.web
http://www.colincochrane.com/post/2007/11/15/Disabling-Configuration-Inheritance-For-ASPNET-Child-Applications.aspx

<location path="." inheritInChildApplications="false">
  <system.web>
  ...
  </system.web>
</location>

No success

Only after enabling  <enableerrorlogging>True</enableerrorlogging>
in the /App_Data/settings.xml, i was finally able to retrieve the error from the file /App_Data/logger.txt !!!

Error message :

Could not find a part of the path 'X:\WebData\Websites\Luuuukke.NET\App_Data\profiles'. 

wtf !!! all this for a missing empty directory (Visual.Studio did not include the App_Data/Profile folder in the web deployment because it was empty.... grrrrrrr)
anyhow, i created an empty "profile" folder in App_Data, and...

it's online now !!