What common error messages can occur when copying files in PHP, and how can they be resolved?

One common error message that can occur when copying files in PHP is "Warning: copy(): Unable to access file". This error typically happens when the file being copied does not have the correct permissions set. To resolve this issue, you can ensure that the file has the correct permissions by using the `chmod()` function to set the appropriate permissions before copying the file.

// Set the correct permissions for the file
chmod($sourceFile, 0644);

// Copy the file to the destination
if (copy($sourceFile, $destinationFile)) {
    echo "File copied successfully.";
} else {
    echo "Error copying file.";
}