Not sure about the backlight issue, as I have no experience with Pertelian LCDs or the driver...
Try setting the backlight slider on the Screen tab under Display Settings to maximum. That might make the backlight come on automatically when Smartie starts. If you've already tried that, then I don't know...
Did the Pertelian driver not work at all (nothing on the display) or did it sort-of work, with perhaps corrupted displays? Did you use the HD44780-serial driver to do the backlight control? I understand the pertelian.dll is out of date and HD44780S generally works better.
As for actions, these generally respond to a change of input condition, and the conditions are checked at regular intervals, I think specified by the DLL check interval setting. As far as I know, there's no official documentation for various Smartie features like actions... high time we got some good user guides written up.
At startup, all the conditions are new, so things like "IF 1>0" will trigger the associated action - "backlight ON" in your case. After that, I don't think the action will be retriggered, because the condition hasn't changed.
Actions are generally triggered by pushbuttons on a compatible LCD unit, media player status (playing/stopped), network conditions (do something if an email arrives)... lots of things. In fact, so many things that it's easy to get confused.
For example, I have some actions that switch screens/themes depending on what I'm doing. If Winamp is running, I show the Winamp info screen, otherwise I show general system info. If I press the play button on my LCD, Smartie triggers an action to make Winamp start playing.
The GPO command in the action output choices controls General Purpose Outputs that are a feature of some LCDs, like Matrix Orbital and Crystalfontz units. The GPOs are basically electrical switches that can control alarm beepers (think of an action for CPU over-temp), LED indicators and even case fans. Some LCDs even offer dedicated fan control outputs, hence the Fan() command.
For example, to turn on GPO2 (there are usually several GPOs), you would put GPO(2,1) as the action. To turn the GPO off again, you would put GPO(2,0).
Hope that clears up your questions about actions!