See my comments on this thread. Unfortunately Mono has not become a stable platform for running mojoPortal. It has worked to some degree in the past for some versions of mojoPortal and some versions of Mono but it has never reached a point of being reliable and I'm skeptical whether it ever will after hoping it would since 2004.
When Mono was supported by Novell they used to make a VMWare image available of opensuse and Mono that I would use for some testing but they no longer do that and testing often revealed Mono bugs anyway. I ahve not shipped a release package for Mono in quite a while now.
Recently I did try updating our .sln for Mono on my Mac, and while I was able to get it to compile and I was able to run the setup page, I could not get it to work on other pages after that, it gave strange errors on internal mono classes. It also gives errors when trying to use the latest AjaxControlToolkit.
I'm still a fan of Mono but I am very close to giving up completely on the idea that it will ever be a stable platform for running mojoPortal. I think their focus these days is on mobile devices and maybe simple web services to support mobile apps can work ok but large complex ASP.NET projects have always been challenging on Mono and I think it is worse today for such apps than in the past.
Sorry I don't have better news on the Mono front.