My instance was quite specific and getting rid of the key in console.exe.config made the error go away, but there might be other ways of getting it.
For example if you are on 2008 and have ftp'd or file transferred the installation files or patches, I've found that some of the files become untrusted. There are other articles/comments from LANDesk on this and you get quite odd results. The app appears to work in some ways, but then gives unusual errors. So make sure all the DLLS are marked as safe (property of the file in explorer properties) as descibed in otehr articles.