Running external tools in Eclipse on Mac OS X

I'm using Flash Builder 4 on a mac. I've created a JSFL file for building a few fla's and then testing my main SWF file. I'm trying to run this JSFL file as an external tool from Flash Builder 4 but when I select Adobe Flash CS4.app as the file to run the JSFL Eclipse warns "External tool location specified is not a file."

I have Parallels inst开发者_高级运维alled and if I point at a .exe file this warning goes away. Is this a bug? Why can't I use a .app as an external tool in Eclipse?

Try this:

Location: /usr/bin/open

Working Directory: empty

Arguments: -a /Applications/YourApp.app --args "arguments"