I created an installer that installs .NET Framework 2.0 as a
prerequisite, which works great, further on in the installation it
places 3 .dlls in the GAC, and then it launches my app, which complains
that the 3 assemblies are not in the GAC, despite the fact that I have
checked, and they are indeed in the GAC.

What's weird is that in my debugging, I installed the .NET SDK so I
could use gacutil which is not installed with the redistributed
framework, as soon as I installed the SDK, the app worked, at which
time I verified that the assemblies were in the GAC.  I then
uninstalled the SDK, and the app stopped working, again stating that
the assemblies were not in the GAC.  I then copied the gacutil over
from another machine, and re-verified that the assemblies were in the
GAC, despite the error message of my app.

I have previously written an installer for this same app, using the
same assemblies and have not had this problem (though last time I used
VS .NET 2003, and I am now using VS 2005).  I have installed .NET from
a redistributable that I had on my disk, as well as a fresh one I have
downloaded.  

I'm stumped, anybody?