Locate the file [XAMPP Installation Directory]\php\php.ini (e.g. C:\xampp\php\php.ini)
- open php.ini in Notepad or any Text editor
- locate the line containing max_execution_time and
- increase the value from 30 to some larger number (e.g. set: max_execution_time = 90)
- then restart Apache web server from the XAMPP control panel
If there will still be the same error after that, try to increase the value for the max_execution_time further more.