Incidentally, the Unknown Error -84 will not occur with 10.1c (The latest version).
While Error -83 is definitely a different issue, I will post the resolution below:
Error 83
This
error can occur any time the AST Service cannot start. This error seems specific to 10.1c. Open the Services section of Windows
(Start-->Run-->Services.MSC) and double click on the AST Service. Make sure the Startup Type is set to
Automatic and that the Path to Executable is set correctly. Sometimes the Path to Executable will have
two backslashes in the path, i.e. C:\Windows\System32\\astsrv.exe. The backslash must be removed. The way to do this is to close the Services
and open the Registry Editor (StartàRunàRegedit). Make sure to left-click on My Computer (So
that you are starting at the top of the Registry) and press Ctrl-F. In the Find box, type \\astsrv.exe and click
Find Next. Each time it finds this, double
click on the registry entry and remove one of the backslashes, then click
Ok. Press F3 to Find Next and repeat
these steps until it is finished searching the Registry. Go back to the Services section and try to
Start the AST Service.
PLEASE NOTE that caution should be used when modifying the Windows Registry. Making changes to other aspects of the Windows Registry could cause Windows to become unstable.