When I drag & drop a dll to the assembly folder on vista, I get the error \"Access is denied: mydll.dll\". How can I bypass the error message and add my dll to gac?
You can do that with gacutil.exe. It is located in:
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727
It is only there though, if you installed the .NET SDK (not just the .Net Redistributible). But you can copy it from your developer machine.