I just tried and same problem :(
As far as I can tell, I'm following all the steps in the documentation:
- Export from Construct 2 and select the Cordova option
- Once the export finishes, open the resulting folder. Add all the files to a zip file. Make sure the files config.json and config.xml are at the root level of the zip, and not inside a subfolder in the zip.
- Open the Export Manager in Construct 3, via Menu►View►Export Manager.
- Click the Add button in the toolbar of the Export Manager and select your zip file.
Then error message pops up again.