GUISkin: Object reference not set?

I did Assets->Create->GuiSkin, on a blank project, and get the error: "NullReferenceException: Object reference not set to an instance of an object". Although I understand what the error means, :) I don't know why I'm getting it on a newly-created Asset. Is there something I'm supposed to create first? The Manual page doesn't mention anything.

Actually, on thinking about it, I'm wondering if it matters... I restarted my project, and the Skin is there, no obvious reason I can't use it. Is this just a spurious error message?

This error is harmless, but a nuisance nonetheless. I'll check the developers have it down for fixing in the next release.