API documentation: LSOpenURLsWithRole()

fbernardo's link provides a good starting point... In this case, it's a more generic error as explained here: https://web.archive.org/web/20191128225313/http://office.mvps.org/error/number.html#error-600

An inability to send a 'launch' event to the mach port sounds like a runtime kernel level issue... in my case, it was a zombie of a process I'd killed form the terminal holding on to certain resources, which only a reboot could solve.

I had the same issue, and found a fix without rebooting. If you Kill the WindowServer the issue with Finder no longer opening windows will be resolved. You will be returned to the login screen, and when you login again Finder should be working perfectly!