[launchd-dev] SMJobBless error: kSMErrorDomainFramework error 5 - The tool at the specified path is not valid

I writing a PreferencePane project and created a helper tool to perform actions that required an elevated privilege. When I run my Preference Pane, I am getting this error:

System Preferences[22312:903] Bless Error: Error Domain=kSMErrorDomainFramework Code=5 UserInfo=0x2005790e0 "The operation couldn’t be completed. (kSMErrorDomainFramework error 5 - The tool at the specified path is not valid.)"

Any ideas on what this error means, how to debug it, what to check?