What information is shown in the releavnt files, ex: Indexserver, nameserver and Daemon trace files?
Always look here for further information. The error you posted is very generic and could be one of 100 different problems.
My guess is you have a log volume full so you will have to create a symbolic link and move the log volumes, Then reclaim the free log volume space with ALTER SYSTEM RECLAIM LOG.
Please provide more trace info in future