troubles declaring static enum, C#

Enums are types, not variables. Therefore they are 'static' per definition, you dont need the keyword.

public enum ProfileMenuBarTab { MainProfile, Edit, PhotoGallery }

Take out static.
Enums are types, not members; there is no concept of a static or non-static enum.

You may be trying to make a static field of your type, but that has nothing to do with the type declaration.
(Although you probably shouldn't be making a static field)

Also, you should not make public nested types.

You don't need to define it as static.When an enumerated type is compiled, the C# compiler turns each symbol into a constant field of the type . For example, the compiler treats the Color enumeration shown earlier as if you had written code similar to the following:

internal struct Color : System.Enum {
            // Below are public constants defining Color's symbols and values
            public const Color White  = (Color) 0;
            public const Color Red    = (Color) 1;
            public const Color Green  = (Color) 2;
            public const Color Blue   = (Color) 3;
            public const Color Orange = (Color) 4;
            // Below is a public instance field containing a Color variable's value
            // You cannot write code that references this instance field directly
            public Int32 value__;
}