While you wait for an answer here, be sure to contact your local Archicad support people.
You could try installing a new BimCloud Manager and Server and copying the contents of the Projects folder from the corrupted install to the new install. The projects may appear as an unlinked project inside the website bimcloud manager interface.
Or alternatively you can import the .archive snapshot in the Backups folder for each project in the Projects folder, or copy the PLN to your main computer and re-share that.
The BIMCloud libraries live in the Attachments folder and I believe you should be able to import the archive files back into the manager the same way.
you will like likely need to relink the libraries to these reuploaded BIMCloud libraries though.