Hello, This error indicates that there is another program at your computer that actively prevents PHPRunner from saving the files.
It can be an antivirus, your web server or app like Google Drive, OneDrive etc. First of all disable your antivirus and build your project. If it doesn't help, proceed to the Output screen in PHPRunner and choose another Output directory there.
Then build your project. Does it make any change?
If you still receive errors, try different paths there.
First a directory within Documents folder, then outside of it, like C:\Output Thankyou