Improve error communication when uploading a import package without proofRead folder

When you upload a zip package without a proofRead-folder in the right position, afterwards you simply get a red and emptied upload field.

Most of the users will not understand what happened and will  not hover over the field and see the message.

The error message must be shown in a promiment way. Best with a pop-up, where you have to click "ok".

In addition I do not have the possibility to select a new package and restart the import, because the "Continue" and "skip next and import" buttons are gone. I have to close the import window and reopen it and refill all params.

Question: What feedback do you get via API?