Hello. I have a little problem with Unity. I wanted import my .blend file to Unity. I did it as it writen on this page here: http://unity3d.com/support/documentation/Manual/HOWTO-ImportObjectBlender.html but it doesn´t work. I gave the .blend file to the assets folder of my project and it was in the project view in Unity but when i wanted move the file to the scene view, nothing happend.
I have Blender 2.49b and Blender 2.5alpha2
and Unity 2.6.
Is somebody here who could help me please?
At the moment the only way to go is Blender 2.49b.
If you have a look at the Hierarchy view, did the model appear there?
I dont know how did it happen, but suddenly it works fine. 
But there is another problem with the model in the scene. The model is smoothed but in the Blender it was not. Can I turn it back again in the Unity?
That is a known problem. In Unity every vertex has exactly one normal. So if you import the standard cube from Blender into Unity, you won’t get sharp edges, but it appears smoothed instead. The easiest way is to experiment with the import settings of the model:
Thank you. Now it realy works fine. 
I´m so glad for your help. Thank you very much.
But what if I make my object sharp but I need one or more of all the objects smoothed. Can I Smooth every one separately?
For example: I have a scene (made whole in blender) and exported whole to Unity) where are for example stairs. I made the whole scene sharp but I need the handrailing to be smoothed. I have tried smooth it separately but it doesn´t work.
Why is it so complicated?
As far as I know the importer was just not made to import whole scenes. You can certainly do that, but as you have noticed it is easier to import model for model.
If I understand right, it means, that I have import steps, handrailing and walls as separated prefabs? If it´s like this, I should import all steps together as one prefab, then all handrailings together as another one prefab and then all walls together as another one prefab?
It is no problem if you have 1000 objects in a Blender file, as long as it is acceptable for you that all have the same import settings.
I meant that the importer was not made to import scenes and have different import settings for the objects within that scene.
I hope this explanation is more understandable.
Thank you very much, now I understand.
I had and am still having this very same problem. When I drag or copy a .blend file into a unity project/asset folder and start unity3d. The object shows up in the “asset view” but when I drag it to the scene view all I see is the axis and no mesh or geometry. I thought it was a scaling problem but even scaling up by 1000 does not cause it to change.This happened 100% of the time.
Now if I use the fbx exporter within blender and export to that same unity project/asset folder the object shows up just fine. It shows up in the scene view and in the project view. With the correct hierarchy.
If you select the Blender model in the “Project” tab, there should be a preview in the “Inspector”. Do you see that preview?
It is hard to help, could you provide a sample file?
I do see it in the inspector panel that is where I increased the scale. I will try to post a test project file later on today.