[otrs] Problem with otrs / sometimes errors in Logfile

Hi there, i have a problem with otrs running on linux. Everything works fine, when I start the apache. After a while I get this errors in the apache error_log: [Thu Oct 30 10:55:48 2008] -e: print() on closed filehandle LOG at /opt/otrs//Kernel/Output/HTML/Layout.pm line 1534. [Thu Oct 30 10:59:09 2008] -e: print() on closed filehandle LOG at /opt/otrs//Kernel/Output/HTML/Layout.pm line 1534. And the user only gets a blank page in his browser ... When I now restart the apache; is come up but the system hangs after some time again., Can anybody help me?