XSJOB won't activate, invalid file content

Hi experts,

I'm trying to get a simple XSJOB working, but HANA Studio repeatedly tells me "Invalid file content" when I want to activate the following:

{    "description": "Queue worker job",    "action": "mypack:myfile.xsjs::myFunct",    "schedules": [      {        "description": "Check the queue every five seconds",        "xscron": "* * * * * * 0:59/5"      }    ] 
}

The package and xsjs files as well as the function exist and are activated without any problems. I can run the function in the XSJS without problems.

What can I do?

Thanks in advance