First, thank you for your purchase.
The problem is caused by php hosting server problem. Your php server doesn't agree the remote file open function.
Please try the next steps.
1: Please download the demo data from next link manually.
2: Please copy downloaded zip file and paste it in wp-content/uploads/lorada_dummy folder.
If there is no "lorada_dummy" folder in uploads folder, please create new one.
Maybe "lorada_dummy" folder will be already there.
3: After paste, please unzip the lorada-dummy-data.zip file in there.
4: Finally, please return your admin import page and try again.
If you have any other questions, please let us know again without hesitation.
Best Regards, C-Themes