I "arm" a scroll and click my mouse button(2), trying both, and nothing happens. The flames sort of sizzle in my hands, but don't fly towards my enemy. Any help would be appreciated.
Thanks.

Which spell is it? Have you held the trigger down instead of clicking it? Higher level spells need to be held down until the animation is finished, then are cast on release.

As Zen1966 has said, what type of scroll is it? If it is fire storm, then you need to hold it down and then do it. if it is a firebolt/fireball spell then you should just be able to shoot it instantly

Thanks to both of you. I will check it out.