I have also gotten that same error.
I had my registered domain name parked and was trying to modify my Main Domain name to it.
I unparked the name then tried to modify the main domain and get the following error:
Hosting Domain Modification
submitted June 29 at 2:07 am
action status
Error
information
A change to your hosting account's primary domain.
result
A system error occurred while processing this action.
Error Code: 1E9F63B0
If I try and re-park my registered domain I get the following error now:
Error from hooks wrapper: Domain action was not successfully completed [1]. Error: Error from park wrapper: cubscout91.info is already configured.
Anyone have any ideal how to get the DNS straightened out?