False alarm or not, NEVER ignore a warning from antivirus!!!
No need to run the risk for infection your system with HEUR/Malware (contains in Setup.exe)
1. unzip “Garmap SubSaharan Streetmaps 2012 NT.exe” (use win rar or 7zip), right mouse click
2. delete all files except the folder "SA Streetmaps"
3. open folder "SA Streetmaps" und unzip "setup.zip", this will give you the folder "SA Streetmaps 2012.gmap"
4. follow the procedure like for any other gmap folder
same procedure for Garmap SA TopoRec 2012 NT which contains two "goodies"