Hi,
We have seen some cases where you can't delete the model when the published model is already deleted.
Please try to re-publish the model again by clicking on the "Publish Latest" icon and then delete it from the Manage Cloud Models dialog (the published model will be deleted as well)
If the icon indicates that the latest version is already published (green icon), open the model and do a Sync with Central and you should be able to publish it again
There are some previous post regarding this issue;
http://forums.autodesk.com/t5/revit-collaboration-forum/deleting-models-from-a360-collaboration-for-...
http://forums.autodesk.com/t5/revit-collaboration-forum/c4r-not-deleting-central-model/td-p/6595664
The root cause is that it tries to delete the publish model when you delete the file in the Manage dialog. Since the published file is already deleted, it will throw an error and fail the entire operation.
Sorry about that, we are working on a solution to this issue.
Regards
Lars-Ake Johansson
Sr. SQA Engineer