I cannot add new appointments to my calendar in Outlook.  

I tried backing up the calendar and deleting the current one but could not
because it is a required folder.

The knowledge base provides an approach for earlier versions of Outlook
which involves starting Outlook from the command line (exchng32), deleting
the calendar file, creating a new file by restatring Outlook once more from
the command line (Outlook/resetfolders) and then copying appointments over
from the backup.  However, this does not apply to the current version.

Any help would be greatly appreciated.

Many thanks in advance,

Phil