Flashing light on that charger means your battery is being charged, once it's charged it will blink slowly to show that its being maintaned.
the one i have looks a little different, from the one shown o website ,
it has 4 led's ,
1 red ( to warn of terminals connected wrong way round , before switching on .)
1 red ( power on)
i amber ( iluminates when battery is connected, and stays on when charging )
1 green ( to show battery is charged, and mainaining)
the first 2 days i used it, it showed amber light , then this goes out , and green light comes on.
the problem today was , although green led was on, amber led was flashing rapidly ( it should go out , when green led shows.),
i presume this is to show a fault of some kind .
hope this has explained my question a bit better.
daz