First, about GACUtil:
Sign the assembly. Sign it. Even if you don't need it in GAC. If you want to deploy it with application, sign it.
(Do you understand that you don't have to put a library in GAC, only if this is a library to be used by your user? Or if it is to be used by more then one product? It is not needed to deploy just one application in several assemblies.)
Sign everything you deploy in binary form.
See this CodeProject article:
Strong Names Explained
Learn the basics of it. This is very important staff, one of fundamentals. Signing assembly takes seconds, but you should understand why are you doing it.
Now, about regsvr32:
This is a tool for registration of COM DLL, please see:
Are you sure you implement such thing?
You need to understand what are you developing, what are you trying to register and why. Do you develop COM? .NET Assembly? Both? Why? Do you really need registration of GAC? If this is just a single software product with one more applications, you many not even need any installations. It depends on your purpose. Start from it. Learn the basics of the technologies you use and clearly indicate it when and if you want to ask another question.
So far, my impression of your method is something I call "kicking a TV set until it starts showing a picture". :-)