This would have to be a Visual Studio Developers prompt in order for it to find the GacUtil command. What was the error that you are receiving?
Another method to check this would be to open up Windows Explorer and navigate to:the folder:
C:\Windows\Microsoft.NET\assembly
In each of the subdirectories, GAC_32, GAC_64 or GAC_MSIL
Do you see any files starting with MicroFocus. in that folder?