Why I can't issue an asset which name is already exist? I got a error as "xcp" is already used.
It's by design.
I don't get it. As "xcp" for example, Some one has issued "xcp" already. And I have some "xcp" and want to sell it. I can't sell it if I didn't issue it, unless I use another name. Why? I mean all the same thing should be under the same name.
because BobsXCPTokens are a different thing from NxtskysXCPTokens. Just issue them like this NxtskysXCP.