Help with setting destination on igo 8

I have the Philippines map which seem to be working..! I can go and look at it, when I set up a destination satnav say's "cannot find path, maps are isolated" anyone tell me why and what I need to do please.

"Maps are isolated" means there is no continuing (digital mapped) road between start and destination.
Mostly it happens when someone makes a long trip using different countrymaps, but not the maps in between.
Example in the USA : from Florida (East Coast) to California (West Coast) and only those 2 maps are on the sd or loaded in memory, but the other states you need to travel through are missing. The road ends and the State boundary. (For Europe there exists a Main Roads Europe map)
I think it can also happen when you travel from island to island and the ferry is unknown.

So it seems that its down to me being in the UK and trying to map around the Phillippines, o.k thank you so much for coming back, I understand a little more now.