Had this issue before, and had to reinstall my App-V server from cratch. Lucky enough it was a lab environment.
But today I had this error again!
A remoting error occurred. Error Code 0000C824
Because App-V 4.5 Service Pack 2 is released some months ago, I upgraded my VAS server to SP2. After the SP2 update, the Application Virtualization Management Console could connect to my App-V server like before!
Probably reinstalling your current Management Server version should do the trick also!