Conditionally avoiding commands during uninstall

[ken rentz]

Our installer calls a 3rd party executable in order to install some device drivers. Unfortunately, this installer has a number of bugs. On of the more annoying ones is that if it is called during an uninstall or rollback, it will occasionally corrupt itself to where is can not easily be uninstalled or reinstalled. Is there any way to detect that we are in the middle of a rollback and skip over this particular component?