That should work. What the "Start raising dimmer level" and "Start lowering dimmer level" actions will do is call startLevelChange(up) and startLevelChange(down) on the selected devices. The "Stop changing dimmer level" action (assuming that's the one you choose) will call stopLevelChange(). You could try going to the device page for the Sengleds and manually running these commands yourself to see if you get the desired behavior. I've tried this with Sengleds and it worked for me. I haven't used RM for this purpose, at least not recently, but my custom Dimmer Button Controller app that I wrote for this purpose calls the same commands and works fine with the Sengleds I've used (aside from the fact that I don't like how startLevelChange(down) will turn them all the way off instead of stopping at the lowest level, but that's just how they work).
I'd also make sure the Eria is sending the events you think it is. Viewing live logging while you press the buttons should show you (if you have info/description logging turned on for the device). If you're using the correct driver (there's a dedicated one for the Eria), it should do this, but clicking the Configure button can't hurt, especially if you manually changed the driver at some point.
If the button events look good and manually running the commands works but RM still doesn't, you could try turning on (at least) trigger and action logging for your rule. That may provide clues into what is happening--or what isn't, as the case may be.