Judgenode Down issue

Dear Team We have hosted Domjudge 5.0.1 in our university, on 27-07-16 we have conducted practice test for our students , we are facing some issue in judgenode each 10-15 minutes it will goes down , i here attached the screen shots of apache error log file,anyone can help me to resolve the judgehost node down issue . We have separate technical wing is here ,i just enquire with them they told it occur due to the problem set time limit . For example one problem time limit have 1 minut after that the judgenode will goes down I think appache error log is not much for identify this problem, if anything more please specify i will update here Thanks & regards Aneesh