something is broken in the 8.2 installer
i've upgraded first from 7.6 to 8.0 and then to 8.2 with no problems
you shouldn't need to use the agentctl. just run the msiexec. you also should be using the msiexec command like:
msiexec /I c:\temp\RSCD-WIN32.msi /qn REBOOT=ReallySuppress
you can look in the msi install log (in c:\windows\temp or %TEMP%). and see if there are any issues. you can also force that log location w/ the /l parameter
the agentctl stuff was requested by the installation manual though...