Norton Anti-Virus software detect Echofon installer as a security threat (WS.Reputation.1) in a certain case.
WS.Reputation.1 is a detection for files that have a low reputation score based on analyzing data from Symantec's community of users and therefore are likely to be security risks. Detections of this type are based on Symantec's reputation-based security technology. Because this detection is based on a reputation score, it does not represent a specific class of threat like adware or spyware, but instead applies to all threat categories.
As of this writing, Echofon Windows is less than a week old. It seems that Norton considers a new app to have less "reputation" and therefore be a potential threat. We assume this warning will go away with time.
Until then, you will need to turn off Norton while downloading and installing Echofon Windows.