Jruby hangs running running rubyspecs

As a note, when I try to test jruby on specs, I get this:

$ mspec -t j language\predefined_spec.rb

jruby 1.7.0.preview2.dev (ruby-1.9.3-p203) (2012-06-14 fb4c77f) (Java
HotSpot™ Client VM 1.6.0_32) [Windows 7-x86-java]
G:/installs/tcs-ruby193_require_winio_fenix-20120130/lib/ruby/gems/1.9.1/gems/mspec-1.5.17/lib/mspec/helpers/ruby_exe.rb:85:
Use RbConfig instead of obsolete and deprecated Config.
…SyntaxError: -e:1: syntax error, unexpected tDOT

p $:.include?(.)
^
F…F…F

[hang forever]. FWIW.
Cheers!
-roger-

Also as a note, with 1.7.0 I get a segfault not present with 1.6.5