I was also encountering the same error while heavy data inserts.i think this is because archiver process r not being able to write all redologs before redologs get filled up.you can also remove some arc files from archive directory and see.
Check the alert file to see the accompaniing ORA error message. Most probably your archiving destination disk is full or you have archiving process set to manual archiving and all your redo-logs are full, so oracle can not switch to new redo-log. In this case you have to perform archiving manualy.
Jurij Modic ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
Archive disk is not full.
Archiving was set to automatic.
I will check the alert log.
My next try will be to make the redo log files
Why is it I can't increase LOG_ARCHIVE_BUFFERS
greater than 5 ?