The simple fix is:
enclose the jruby.home value in single quotes. (this works in the admin console)
The most likely explanation is that this is encountered on Windows because every file path contains a : (colon) which "is a separator for --property subcommand of asadmin deploy".
I'm all for *nix, but classifying a bug like this as Resolved/Invalid seems a little ignorant when every file path on Windows contains a : (colon) and will generate this error.
This workaround was mentioned in the bug report linked above by Vivek:
https://glassfish.dev.java.net/issues/show_bug.cgi?id=10322
[Message sent by forum member 'gbridout']
http://forums.java.net/jive/thread.jspa?messageID=473430