Sender File Adapter - FTP Connection Error 530

Need help!!!

I am getting the following error in XI when I try to connect to an ftp server.

"An error occured while connecting to server xxx.xx.x.xx:xx. The FTP server returned the following error message:'com.sap.aii.adapter.file.FTPEx: 530 Can't open passive connection---(4013)'. For details, contact FTP server vendor"

When I try the FTP connection on the OS level I am able to log in, but through XI I am unable to.

Has anyone seen this error before?