This article applies to Windows Vista and above.
If you are using a non-admin windows account, Voobly setup won't create the required registry keys for all users.
Voobly Technical Support has confirmed that this is a bug with older installations of Voobly, as the error might still occur after upgrading.
Please find the attached fix below.
Windows Registry Editor Version 5.00
@="C:\\Program Files (x86)\\Voobly\\voobly.exe"
@="\"C:\\Program Files (x86)\\Voobly\\voobly.exe\" %1"