The Problem:
I need to launch a background-application from inside the application-support directory. The OS is Mac OS X 10.5.1 build 9B18.
[[NSWorkspace sharedWorkspace] openFile:path];
where path is the correct path to the application, in my case "/Users/user/Library/Application Support/IMLocation/IMLocationHelper.app.", works about 3 out out 4 times, but intermittently fails. It also reports success without actually launching IMLocationHelper.app, but this is far more rare.

Details:
When openFile: explicitly fails, it prints, "LSOpenFromURLSpec() returned -600 for application (null) path /Users/user/Library/Application Support/IMLocation/IMLocationHelper.app." to stderr.

Error -600 is procNotFound /*no eligible process with specified descriptor*/.

The path is correct, the application exists there. I verified this by
assert([[NSFileManager defaultManager] fileExistsAtPath:path]);
before calling openFile:.

Calling openFile: again immediately after a failure often works

Also, while(![[NSWorkspace sharedWorkspace] openFile:path]);
will terminate, meaning it reported success at some point, but it will not always have actually launched the application at path.

(EDITED TO ADD: At first I thought that, NSWorkspace was probably opening IMLocationHelper, but not blocking until it has finished being launched. But sleeping, to give IMLocationHelper time to finish launching, did not solve the problem.)

performSelectorOnMainThread did not solve anything ether.

I verify that IMLocationHelper has been launched by
assert([[ShellTask executeShellCommandSynchronously:@"ps -axww | grep IMLocationHelper | grep -v grep"] length] > 0);

A Workaround:
[[NSTask launchedTaskWithLaunchPath:@"/usr/bin/open" arguments:[NSArray arrayWithObject:path] waitUntilExit];.

This calls the open command to launch the application. I have not been able to make it fail when path exists.