I have Windows application written in VB.NET that implements a file upload feature to a FTP server on a Main frame computer. I use FtpWebRequest class in System.Net namespace to create the connection but I keep getting errors. I search the Web and seem like quite a lot of questions like my errors have been asked but I can not find any answer yet. The errors I got usually errors number 501 or 550. Any body the aswer to this problem, please help.