HOTFIX: You may be unable to use an FTP application to upload a file to a remote server on a computer that has Internet Explorer 7 installed
On a computer that has Windows Internet Explorer 7 installed, you may be unable to use an FTP application to upload a file to a remote server.
This problem occurs if the application is based on WinINet FTP functions.
This problem occurs because of an access violation that is caused by the InternetWriteFile WinINet API function.
When you use an application that is based on WinINet FTP functions to upload a file to a remote server, the remote file is created by using the APPE FTP command. However, when the operating system tries to use the InternetWriteFile function to write the file, this access violation occurs.
http://support.microsoft.com/default.aspx/kb/934376
“HOTFIX: You may be unable to use an FTP application to upload a file to a remote server on a computer that has Internet Explorer 7 installed”