No, experimenting with admin login will not solve the problem. On the contrary, Zorro won't connect to a Metatrader that belongs to a different user. Also, do not run a ticker or similar MT4 support program.

Next step. Close both Zorro and Metatrader. Now locate the temporary folder on your PC. It's normally Users\(your name)\Appdata\Local\Temp. But if your OS is from before 2006, it can be just C:\Temp. Start MT4 again and check this folder. A file "mt4mapd.sys" must appear in this folder as soon as the Zorro EA is running. Do you see that file?