"lein repl" malfunctions in Emacs (24.3.1) subprocess?

[cohagan]

I'm trying to use Emacs as my dev environment for Clojure programming under 
Windows 8.1. When I open a subprocess (via M-x shell) I get a command prompt as 
expected. I can then run "lein test" and my unit tests are run as expected -- 
with output to the shell buffer as expected.

If, however, I enter "lein repl" then the REPL starts as expected, but is non 
responsive. For example, if I enter (+ 1 2) at the user=> prompt (followed by 
Enter) I get no response at all.  The input isn't echoed (as expected) and no 
output at all appears.

Note that "lein repl" runs fine at a normal command prompt (or within a 
subprocess buffer in Epsilon (an Emacs clone.)) This problem occurs on 3 
different machines.

This has worked for me in the past so obviously something has broken, but I 
haven't a clue what it might be or how to troubleshoot.

Any pointers/suggestions would be greatly appreciated.

Thanks in advance,
 Bill