The resource would be a problem because even a single resource could lead to such problem.
I too had similar issue but found this solution:
- Edit your Unlimited Plan from Hosting Plans :: My Plans :: Edit Plan.
- It would throw an error alongwith the resource which is cause of all problem. View Error Report.
- You can either exclude this resource or sell a quota to the end user or reseller under which you are facing this issue.
This would help you in sorting out quota violation issue and then you would be able to import websites into HC panel too.