You will need to download and apply the "Old Save Compatibility Patch (For saves from 0.34 and older)" from the download folder. A plugin in version 0.35 broke old saves, but applying the compatibility patch fixes this. You'll also want to apply patch 0.37.13 to the game as well, and then once in the game go to the debug item and activate compatibility mode. (Patch 0.37.13 fixes a bug with compatibility mode.)