JSpec command line run command doesn't work

[P. A.]

Hi.

I've just installed the JSpec* gem and trying to run some test suites.

When I type:

jspec run
jspec run --browsers ff
jspec run --browsers ff --server

I receive the next warning and an error report:

<gem_dir>/gems/visionmedia-commander-3.2.9/lib/commander/blank.rb:5:
warning: undefining `object_id' may cause serious problem
error: wrong number of arguments (1 for 0). Use --trace to view
backtrace

How can I fix the bug and what's the reason?

OS: Debian 5.0.2
Ruby: 1.9.1
JSpec: 2.10.0
Firefox: 3.5.2

Thanks.

* http://visionmedia.github.com/jspec/