Hello there,
We got the same issue but in the latest version 8.0.4 (announced as 8.0.5).
Only possibility to be able to import the report zip again is to delete everything concerning these reports. Meaning: Delete all Reports and all the referenced ReportDefinitions.
Now comes the problem: If you're using a CUIC standard license, you don't have any access to the ReportDefinitions. Voilà you're unable to import the reports again if the ReportDefinitions has changed. If they haven't changed and the ReportDefinition with its referenced ID is still available, deleting the Report will be sufficient.
Pay attention to the permission assignment. They probably need to be redone.
Cisco simply did NOT implement any Update possibility...
@ Joey Wang: There are several reasons why a customer would like to import the same Report-Package again. Most commonly: They changed the original imported Report and would like to restore the initial version. Or else: they would like to import the corrected version of the reports.
@ David Chumbley: I guess if you are using a Standard license your only chance is to open a TAC Case. Please let us know what Cisco intends to do with this

Cheers,
Stefanie