ExecError is raised for errors in executing a command line using the Exec class or system(). Normal raising of this error causes the joblet to fail. Put this Error in an try except block to handle the error.
Example to handle an ExecError:
class MyJoblet(Joblet):
def joblet_started_event(self):
try:
e = Exec()
e.setCommand("ls -la")
e.execute()
except ExecError:
print "ls failed. but okay to continue"