How can PHP developers troubleshoot and resolve errors related to file access and directory navigation in their code?

When troubleshooting file access and directory navigation errors in PHP, developers should first check the file permissions to ensure the script has the necessary access. They can also use functions like `file_exists()` and `is_readable()` to verify if the file or directory exists and is readable. Additionally, using `error_reporting(E_ALL)` can help identify any errors related to file access or navigation in the code.

// Check file permissions
if (!is_readable('file.txt')) {
    echo 'File is not readable.';
}

// Verify file existence
if (file_exists('directory/file.txt')) {
    echo 'File exists.';
} else {
    echo 'File does not exist.';
}

// Enable error reporting
error_reporting(E_ALL);