Hi!
I think your problem is similar to casting a List to an IList<string>. This is not possible because the two types are unrelated, and it does not matter what they contain (and you have no guarantee that the List only contains strings either...).
Anyway, you might solve your problem by not using generics or you could switch to the correct Spring.Data.Nhibernate dll. The one with generic support is called "Spring.Data.Nhibernate12.dll".
If you are using HibernateTemplate with generics support then your find would look like this:
Code:
IList<Aboutusdetail> list = HibernateTemplate.Find<Aboutusdetail>("SELECT a FROM Aboutus a WHERE a.Id=?", 1);
You can also take a look at this thread in the Spring.Net forum:
http://forum.springframework.net/showthread.php?t=686