Did you download one of the packages specifically for Mono? Those packages should be targeting .NET 3.5.
Makes sure you download one of the packages that has "mono" in the name, ie mojoportal-2-3-6-6-sqlite-mono-deploymentfiles.zip or mojoportal-2-3-6-6-pgsql-mono-deploy,mentfiles.zip
Of course whether it works is still likely to be hit or miss as I said before, working with Mono for ASP.NET has always been a "your mileage may vary" kind of thing.