I have over the past few days been trying to install Blender OgreXML (or OGRE Exporter as it is also called) and have finally managed it (thank God), however, it didn’t go quite as smoothly as the documentation suggested and i’ve definitely produced a hacked solution. So I thought I would go through what I did in case something other than me isn’t quite working properly. And either way for anyone experiencing the same problems to find
-First I installed Blender
-Then within JMonkey Engine I selected Tools>OGRE XML>Install Blender OgreXML, and selected the scripts folder within blender, for me this was C:Program Files (x86)Blender FoundationBlender2.64scripts
-This correctly adds ogremeshesexporter.py into the addons folder. However when going into blender to activate the plugin (Within Blender:File>User Preferences>AddOns) the plugin (called Import-Export: OGRE Exporter …) appears with a warning “Quick Start: ‘.mesh’ output requires OgreCommandLineTools (http://www.ogre3d.org/download/tools). [Is this supposed to happen or should JME have installed the dependencies?]
-Regardless I download OgreCommandLineTools from the suggested link and after I (eventually) realise that they are not installer .exes but the tools themselves I put them in what is stated as the default location (C:/OgreCommandLineTools) and for good measure also directly in addons and addons/OgreCommandLineTools. This does not remove the warning message
-I therefore install blender2OGRE as it promises to (as a side effect) install OgreCommandLineTools for me. This successfully removes the warning message but is clearly a hacked solution
I get the warning also, never bothered to install the command line tools and the simple stuff I do works anyway 
I only do UV-mapped models (meshes basically), no animations, no lights et c.
But recently I just convert directly from the blender model in the SDK and not bother with the Ogre step.
Unless you need animations then the direct blender importer works very well (that’s what we use too). Last I heard animations are not supported on the importer though…
I’m so glad I found this thread, I’ve been really struggling to get models out of Blender. I didn’t even realize that JME3 has a built-in importer. Thank you all, I was pulling my hair out.
Install the Blender OgreXML file in Blender\2.63\scripts\addons, then close and open Blender and go to User Preferences and under Add-ons there is a tab Disabled, find the ogre import in there and check the box. Then save user settings and everything should be good to go.
Ummm, this thread is 4 years old you know.
haha ye saw that now 
However. Let me ask a question. Does ogre i/o addon works with latest Blender? Why I always fail exporting animated model. It’s exported but can’t be read on jmonkeyengine.
I haven’t even managed to get it installed with the latest version. I have Blender 2.73 saved just to export animated characters.