Please make sure that the uploads folder (FTP -> root folder/booking/uploads/) has CHMOD 777 and check $baseDir in /booking/includes/dbconnect.php.

If you’re using filezilla to upload files to your ftp:
Connect your FTP client to your web server and then locate the /booking/uploads/ folder. In FileZilla, right-click the file on your web server and choose File Permissions to open the file attributes. Type the correct number in the Numeric Value text field.