What could be potential reasons for a PHP script not working properly after following all the installation steps?

One potential reason for a PHP script not working properly after installation could be due to incorrect file permissions. Ensure that the PHP file has the correct permissions set to allow it to be executed by the server. Additionally, check for any syntax errors or missing dependencies that could be causing the script to fail.

```php
chmod("your_script.php", 755);
```

This code snippet changes the file permissions of "your_script.php" to allow it to be executed by the server. Make sure to replace "your_script.php" with the actual filename of your PHP script.