[Haskell-cafe] Virus alert while installing happstack

Hi, I tried to install happstack via "cabal install happstack" on my WinXP system. While installation progress, my anti-virus software (Avira AntiVir) warned me about dll_hsc_make.exe and files_hsc_make.exe to be a Trojan horse called "TR/Dropper.Gen". It's a bit confusing to get a virus alert while installing Haskell packages. Has anyone experienced this problem? And can I trust these files to be harmless? Besh wishes, Maciej