Please make sure you:
1. Download and install MC.
2. Restore your license. The version of the license must match the version of MC that you have installed.
Please read this:
https://wiki.jriver.com/index.php/Restoring_a_LicenseAny license should also work with the latest builds of the previous version. For example, an MC31 license will also work with MC30.0.91 or higher.
Still have questions? Just ask.