db connection

hi all, i got a problem. i am dealing with a small program whose function is listed below: - get a connection to database oracle 8i using using ocilogon - execute some commands with database - logoff as it may cost long time (more than 10 hours) to finish exciting all commands, i have to keep the connection all the time. however, it always break up abnormally and unexpectedly when running (return ora-03113 error), isn't it strange? is there anyone met odd things like this? how did you get it solved? thanks Joyce