Thread:Project:Support desk/User preferences give internal error!

I'm receiving this: [b3bbedb6] 2012-06-08 01:22:41: Fatal exception of type MWException

I'm using 1.20 alpha as the installation of 1.19 was unsuccessful, it gave me something like: "php exited unexpectedly" or something. I know that this site uses 1.20 aswell but I don't know if I have updated it frequently enough (I installed it last month and never upgraded) is there anything I can do?

If I need to update then please tell me how to with the minimal disruption of my site.