Vista - Self installing programs

I have a few programs that need installing and is an addon to a game which
works fine in a windows XP SP2 machine.

Now I go and buy a new computer with Windows Vista Home Premium installed.

The error I get is this.

Cannot Load "launcher" Function in
C:\users\XXXXXX\appdata\local\temp\gert0.dll.
it then pops up a window stating that it is a virus a
TrojanSpy:win32/banpaes.X
and yet I can install this on an XP system without problems. and without a
virus checking program going off.

Anyone got an Idea what that is? or how to fix it?

it is one of those simple installers like clickteam or qsetup.