I suggest you go through this guide carefully: https://qloapps.com/install-qloapps/
And please make sure your server configuration is compatible with QloApps. The required server configurations are also given in the guide.
This issue generally arises because of the sql_mode variable value of your database.
We have resolved the issue. Please download a fresh QloApps and replace attached files in the below paths respectively.
Please ensure that the owner of the web server is the owner of the directory as well.
If they are not same then make them same and then try to install QloApps. And if still, you face any issue then please inform us.