What does this mean?
If you enter your PIN and then click the Accept button to accept a particular job, this message may appear to let you know that the job is no longer available. Between the time that you click the Details button and the time that you clicked Accept, this job was either deleted or edited by the teacher or administrator.
How do I fix it?
Not a great deal can be done for this. In this case, the state of the job has been changed to a state where it cannot be accepted (it is either being edited or was deleted). If the job is currently being edited, it will reappear on Jobulator once the teacher or administrator save the changes. Try automatically refreshing your Jobulator by clicking the Refresh button. The job will likely disappear. If it reappears, it should be ready for you to accept.