This happens sometimes if you are running a software firewall, such as Zone Alarm, or a hardware firewall.
Resolving this issue is simple. In US DataVault Backup Pro, go to:

- Edit Backup Schedule
- Choose your Schedule, then Click 'Next' twice until you get to the screen that shows 'Select the device to backup to' on the top left corner
- Under 'Enter the FTP Server to use' click 'Edit'
- Uncheck the 'Use Passive FTP' box
- Click Save, then click OK, Click 'Next' twice, and click Finish.

This should resolve your issue.