I get error "SAP System Message:N" more often

Dear All,

     i get error message "System Message N" more often means at least once in a month, then i have to restart the system and error gets resolve.

     But business have to wait in between restarting the system.

     we are using Suse Linux 11 and SAP Sybase ASE 15.7

     few points i would like to mention

     1) Transaction logs Runs correctly

     2) File system has enough space

     3) in ECD.log file one error i can see is that "Unable to insert task into scheduler as the scheduler has already shutdown."

Thanks and Regards,

Murtaza