Problem description: during restore of a subsite following error occurs: parent web does not exist

I had exported a subsite having over 50 subsites beneath it using the stsadm -o export command. Upon importing the hence created backup file using the stsadm -o import command on another server, a fatal error occurs. The error logged is: FatalError: The file cannot be imported because its parent web <URL name of the exported subsite> does not exist.

Solution: do the import as site collection administrator

My first thought was that I needed to create a blank site with the same URL name before importing my subsite. So I gave it a try: my import started better, but it failed again, on the first of the more than 50 subsites beneath my "parent" subsite. So I created again a blank site for this sub-subsite. My import went already some further, but then it failed -off course- on the second of the more of 50 sub-subsites. I couldn't believe I would need to create my complete site hierarchy before being able to import my backup of a subsite. Then I tried to do the import with another user account, and hey, the import ran smoothly without any errors. So what was the difference: my second account was a member of the site collection administrators group.
Conclusion: running an import of a backup of a subsite should be done with a user account being member of the site collection administrators group, else you get some cryptic error messages and a failure of your restore operation.