That may be a security problem with your machine. Antivirus, etc.
Or you may have a 32-bit OS. Try downloading and installing the 32-bit version of MC.
Is the file extension correct?
What is your OS?
Taken directly from a system check: Windows 10 Home Ver. (x64) 21H1 (build 19043.2251) / Windows Feature Experience Pack 120.2212.4180.0.
I am quite sure it is 64-bit but if you want me to try installing the 32-bit build of MC 30 anyway I'll try it.
I am using an Administrator level account. For troubleshooting I am trying to run C:\Programs\J River\Media Center\Media Center30.exe directly from Windows Explorer view and each time I use the Run as Administrator option. As expected a dialogue box comes asking if I want Media Center to make changes to my system. I click yes.
My security software is Bitdefender Internet Security build 26.0.30.102. But for troubleshooting I am turning off all that it defends: Antivirus, Firewall, Vulnerability, Spam. It's off right now as I try to troubleshoot. Have not given Windows Security the option to take over although, as expected, it notifies me I should do so. Bitdefender is very good at logging all it's notifications and there is no notation of it seeing or doing anything related to MC 30. Other than Bitdefender and Windows Security I do not use any other security software.
I know how to run Computer Management so can check events stuff if you want to tell me what to check. I know how to navigate the registry though I am shy about making any changes unless I know exactly what to check and what to do.
In the 2-yr life of this PC and account I have downloaded a lot of software from the web and installed with no problems. As a test last night I installed some freebie utilities without problems. That suggests the problem lies specifically with trying to install/run this package of MC 30.
Another route to try though I will wait for your comments. I have a new laptop (Windows 11 Pro x64) and can try to install the same package to that and see what happens. In fact my goal was to update from MC 26 to MC 30 on this machine then after that install MC 30 on the labtop.