yes, puzzling, because i never encountered this... does -verbose say anything more? Also, did you recompile flext and py for Miller's PD version before loading? (it is necessary)
just a guess, but can you try to comment out the line 31 in s_stuff.c to turn of external namespaces?
i'm not really familiar with iohannes's changes to add the namespaces, but it's the difference between devel_ and stable_, that's closest to external loading ...
thanks ... tim