Thanks again ixion.
We do not backup online logs at the moment. It was our understanding that all that is required to get the database back up to the current point in time was to apply the archive log and the error we had was asking for the archive log.

This log was on the backup yet it was as though Oracle ignored it. If we backup the online logs and restore them to the backup machine won't that upset Oracle?

With regard to setting up as standby database, I could not find much information about doing that with version 7.3.2 - Can you suggest where I can get some help/information or can you suggest another way to achieve our goal?

Also once the database is recovered, should you not be able to apply further archieve logs to bring it forward in time without the use of online logs if the database is running in ARCHIVELOG?