yap, it looks there are some issue loading the objects. if you go to Browser list and then launch jit_expr help, then you'd be able to load the object.
I also tried creating [jit_expr/jit_expr] that returns an error: jit/expr,expr~,fexpr~ version 0.1 maximum object loading depth 1000 reached
but after that I'm able to load the object.
I'm using Pd 0.48.0 on Linux 64bit
cheers,
Mario