I've read several answers but none that actually seem to fix anything for me. I'm running 32bit Windows 7, and installed Blender from the installer, not from the zip. I first tried Blender 2.55 and the importing didn't work. I then installed 2.49b which is what everyone said was the one to use. It gives the same error:
Blender could not convert the .blend file to FBX file.
Is the original blender file in the 2.55 version? As far as I know, Blender 2.5+ support hasn't been added to Unity yet since it hasn't been stabilized for release yet. You'll need to backsave it with 2.49b if it's a 2.55 file.
If the error persists, open blender and manually export it with the fbx exporter to debug why it's failing.
Have you installed the right Python version? Check your Blender Console after starting, it should write something like :
Compiled with Python version 2.6.2
Checking for installed Python… got
it!
If it is not installed load it http://www.python.org/ , you need a Python 2.6.x release for Blender2.49b!
Edit: Respond to your comment On Adam Rademachers Answer!
"I do not see FBX as an option for Export. I see VRML 1.0, DXF, and STL"
Blender has more than 2 dozens of exporter Scripts(including a FBX Export), if you dont see them something with Python is wrong. As you wrote you installed Blender2.55 before the 2.49b version. Search the Harddisk and your Registry for unistalled Blender related crap and remove it. Maybe you also make a clean reinstall of Phython and then Blender2.49b.
Blender automatic fbx export won't be working with Blender 2.55 until it is no longer in Beta. Apparently there is something broken with its python. There's a forum thread about this where Unity's asset pipeline guy explains.
See this link. It explains having to move the scripts folder. http://wiki.blender.org/index.php/Doc:Manual/Introduction/Installing_Blender/Python