Dial/Generic.78F5 is classified as a Dialer.
Dialers are programs that utilize a host's modem to secretly dial phone numbers.
The Fortinet Anti-Spyware Research Team is currently in the process of creating a detailed description for this Spyware.
For additional information about Dialers, and how Fortinet classifies Spyware threats please see Fortinet's paper in PDF format:
Spyware Classification and Terms.