How do I install the Mono Framework on my Mac running OS X Mountain Lion?
When installing Fender® FUSE™, you will first be prompted to install the Mono Framework. To install the Mono Framework, please see the instructions below.
On the first screen, click Continue.

Click Continue on this screen as well.

Here again, click Continue.

After reviewing the End User License Agreement, click Agree to proceed.

Next, click Install.

Here you will enter your User Account name and password and click Install Software.

Once the Mono Framework installation is complete, the Quartz X11 installer will launch.
Click Continue to to close the Mono Framework installation and continue with the Quartz X11 installation.
Installing Quartz X11