Symbolic logic game shows strange strings instead of the premises

[Thomas Mitterfellner]

In the symbolic logic game, rather than the premises being shown, strange character sequences appear (see attached screenshot). My wild guess is that there's something strange going on with the result of the FlattenPremise function because if I pass a string like "foo" as the result, it is indeed show normally in the game window. (opensuse 12.1, x86_64, precompiled package as well as when compiled from source, versions 0.50 and 0.61)