As Register says, these subjects are well documented elsewhere on the forum. Arctools only seems to load a working version of Android Market if you also choose to alter the software from stock version to the custom version, during which process it gives you Android Market - this is quite a big step to make if you only want AM. Don't forget that AM still doesn't know which phone/tablet you have as the Arnova range is not listed, so it restricts the amount of apps you can have.

There is a well-documented way to load Google apps including AM manually. You'll find it easily if you use this site's search facility. It involves downloading a .rar file, unzipping it and putting the files into your Arnova via USB. Then you install them in a precise order.