expt with rationals hangs openmcl

Hello,
I'm using openmcl 0.12.1 on OS X, and I've noticed that whenever I try
to use expt with a fractional base (for example, (expt 1/2 -2)) openmcl
just hangs, it never returns a value:

? (expt 0.5 -2)
4.0
? (expt 1/2 -2)
> Break: 
> While executing: #<Anonymous Function #x25938E>
> Type :GO to continue, :POP to abort.
> If continued: Return from BREAK.
[...]


-- 
Cliff Crawford                   ::                   cjc26 at cornell dot edu
It goes against the grain of modern education to teach children to program.
What fun is there in making plans, acquiring discipline in organizing thoughts,
devoting attention to detail and learning to be self-critical?  -- Alan Perlis