(Yes I know it is an old question...)
It can be helpful to understand how spelling has changed over time, to know what to search for.
In the example from Norway we have Spilleren in Meløy. Meløy has the modern spelling of the word island, "øy". In the old Danish spelling used in Norway during the union (up to 1814, and beyond) it would be Melø. (As in the link Sylling provided).
Spilleren is now from what I see spelt Spildra. I'm not sure why ll has changed to ld, it usually goes the other way, but anyway this is just variants of the same. Same thing with nd, it can be nn.
And the ending -en and -a are the same, -en being the older and -a being modern/colloquial/dialectical. It means "the" so Spilleren is The Spiller.
In the modern map at http://kart.gulesider.no/?q=nedrespildra we see Nedre Spildra (Lower Spildra) and Øvre Spildra (Upper Spildra) so the farm seems to have been divided.
Possibly Spildra is originally the name of the river. We also see in the map Spilderdalen (the Spilder valley), Spildervatnet (the Spilder lake, could also be -vannet or -vandet in old spelling), and more.
I guess it boils down to the fact that knowledge of the language and its history is very helpful.
PS: Here is a a video of the area: https://www.youtube.com/watch?v=-jdOdyFOl2g