I got this error message on a server while installing Dynamics. At first I thought the problem was that my IIS is running 64 bit .NET 2.0 (I’ve had problems with that in the past), but it turns out that the actual problem is that .NET 4.0 was installed.
This guy figured out what the problem is: The installer checks for a specific filter in the IIS settings, which doesn’t exist when .NET 4.0 has been installed.
I’ll repeat the fix here, hopefully making this a bit more “discoverable” by search engines (searching the exact error message gave me nothing helpful, just tips about running aspnet_regiis.exe -i repeatedly):
In IIS Manager, right click Web Sites, and select Properties.
Under ISAPI Filters, Add a new filter you call ASP.NET_2.0.50727, pointing to C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\aspnet_filter.dll (assuming 64 bit server, otherwise substitute Framework for Framework64).
Dynamics should now install without issue.
Derek
on Jul 8th, 2010
@ 18:51:
I usually don’t leave comments, but your post saved me. I have been researching this issue for quite sometime now. Thanks.
ajnar
on Jul 12th, 2010
@ 10:43:
Thanks a lot, had been really losing hair over this one.
Cheers
fnbrowning
on Jul 16th, 2010
@ 16:34:
THANK YOU for the solution! What makes the Internet a resource is people helping people!
Lars Erik Jordet
on Jul 16th, 2010
@ 17:22:
It’s very nice to see that this actually was useful
I feel a bit bad about this one, as I rewrote it from the article I linked to, but I guess this one is easier to find when searching 
Sérgio Salazar
on Jul 26th, 2010
@ 15:55:
Tanks Mate… your post save me many many time
Beeh
on Aug 4th, 2010
@ 18:53:
Thanks a million man
Vladimir Sergienko
on Aug 5th, 2010
@ 20:05:
Eurika – thanks, this one ate up a few hours of scavenging the void, thanks for putting it out there.
John
on Aug 9th, 2010
@ 03:41:
You’re a wonderful human. This appears to be one of “those things” that is in a google haystack to find and figure out.
Thanks for making a page just for it.
Dimitris
on Sep 15th, 2010
@ 15:28:
I must have really messed it up!
I continue having the same problem!….
Any further help, please?
Marcello
on Sep 22nd, 2010
@ 13:21:
I tried this solution but the setup issues the same message…
Hope someone can help me here…
Thanks in advance!
RobertM
on Oct 1st, 2010
@ 22:02:
omg! you are the man! Thanks so much.
Kza
on Oct 31st, 2010
@ 14:33:
GREAT!!!!
Thanx. Thanx. Thanx. Thanx.
Greg
on Jan 5th, 2011
@ 23:10:
This post saved my the remainder of my hair. It is GREATLY APPRECIATED!!!!
Grateful
on Jan 19th, 2011
@ 12:41:
Life saver!
Thabz
on Mar 30th, 2011
@ 11:47:
Great post…. Thanks
Leon
on Aug 3rd, 2011
@ 14:44:
You a god! Thanks Man!!!