Hello!

> Can anyone shed some light on why this may have occured?

Look here
http://www.ibsurgeon.com/interbase/firebird/error/commonerrors.html#cannot_f
ind_tip_page

> The last thing I had done was to develop and test a restore function
> of the database using iboAdmin components. I have created the
> database using a trial edition of IB Manager

I don't think your error is related to backup/restore.
Possible reason is power loss or abnormal termination of fbserver during
some intensive operation when a lot of transaction were started/ended.

Sincerely yours,
Alexey Kovyazin
www.ibsurgeon.com
www.ib-aid.com