i cant seem to get unity to properly import a blender mesh. It keeps telling me to use a version of blender equal or higher to 2.45. But since i am, this error message does not provide me with enough information to further analyse whats going wrong. I am running Vista Home Premium 64bit edition. Anyone else has experinced this problem?
You need to get the newest 2.49.2 version. There are several issues with earlier versions as far as I know.
Knowing a bit about Windows, Unity 3D just looks for a particular registry key to locate the Blender install. Question is, what is the key? If you know that, then you can manually edit the registry and all should be well (assuming you are using Blender 64 sans installer, for example).
Make sure that you have python installed. If it's not installed, the command line window that blender shows when it starts up will tell you. This website has instructions for installing the proper version.