The Vista operating system includes increased security features that sometimes get in the way of ElephantDrive's ability to function smoothly. These security measures are the likely cause of the problem (the ElephantDesktop probably does not have permission to write files to the directory to which you would like to download).
You can correct this by setting the program to always run as administrator. To do this, please use the following steps:
1. Find the application file, usually located at "Computer --> OS(c:)--> Program Files --> elephantdrive --> ElephantDesktop"
2. Right-click the program icon and click Properties.
3. On the Property sheet, click the Compatibility tab.
4. Under Privilege Level, select the Run this program as an administrator check box, and then click OK.