Normal map bake problem

Hi everyone,
This is my first post so excuse me if I posted at the wrong place. I recently encountered a problem while baking normals of high poly object to low poly object. I have no problem doing this for my own models modeled in blender. But last time I tried this with an exported FBX model. I did the same procedure and created low poly model. But when I tried to bake it gave an error message. It said that my high poly model is not a mesh or cannot be converted to mesh. I tried to google for it but couldn’t find any solution. Any suggestions about what I should do? Thanks in advance.

What was the model ?
Was it a mesh object ?

Please supply demo blend file so that when we press the bake button the error shows

this was not made for you, but it shows how to do what you wish to do.

Thank you fro the replies. Blend file is approximately 600 Mb so this is not an option but the model is in the following link
http://3dsky.org/3dmodels/show/mnoghokvartirnyi_dieviatietazhnyi_zhiloi_dom_2
May be this willl give an idea.

For the video I am already able to do that procedure for the model I create in blender. I just have problem with an exported model.
If you guys need any more information please tell me and I will give you if I can.

This is not a good enough reason for you not supplying a demo blend file.
If the model is large then just delete 99% of if for the demo file ! As long as it clearly demonstrates the problem, that’s the important thing. Supply this file set up so that all we have to do is press the Bake button and the error will show