Bringing a clothed CC character back from Blender I get this error.
Seems to only be happening with a new fully clothed character.  
No modifications were done to the base mesh.
Clothing was modeled and married to the rig per this course: 



... and exported from Blender as instructed... All the settings, exactly the same.
And I'm careful to include the fbx key file on import.
I receive this error if I attempt to FILE > IMPORT or CREATE > CLOTH
As you can see from my screenshot below, everything is selected before export... all the bones... all the meshes... 



That being the case, I don't know what this error even means: 



Incidently - this doesn't seem to be a problem for 3DX7:



Hello again, and thanks in advance 

There is gotcha that can happen with Blender, and it "gotted" you. Blender does not fully release things like materials when you start a new file (File/New). What happened in your case, is that you ended up with a second armature named "Armature.001". That throws off CC so that it cannot find anything.

It is good practice with Blender to actually quit and restart every time you start a character. So if it screws up like that, always reboot Blender and start again to see if it's fixed.

Excellent sleuthing, Rampa.  Thank you.
Just FYI, simply changing the name of the Armature didn't work.  I ended up re-importing the base mesh FBX and redoing the whole clothe-mapping workflow.  
Of course, I have to make sure all my base mesh skin textures are lined up, otherwise CC chokes again... Not sure why this happens, when I import just the base mesh back into CC from Blender, everything is fine.  
I explained to my wife this morning that doing this character creation stuff is like working an algebra problem... mess one thing up and you're sunk!  

** UPDATE**
I solved the missing base mesh texture issue by changing the export "path mode" to "Relative": 



But now I'm getting the Missing Hip Bone Error...  This is like playing WACKAMOLE!  

Thanks again!

It used to fool me all the time!

Do make sure to re-start Blender. Don't just use file/new, or you'll still have the issue. Blender does not "clean its pipes" otherwise.

Restart Blender... Got it...

This missing bone issue is strange.  I saw one other post about this, but the guy was not using blender...
Getting all the bones in the armature is actually a bit tricky in Blender.  In this screenshot I emptied out this particular layer of everything but the stuff I'm trying to select (no lights = black mesh)...  So I just did a quick A to select all... but then I actually selected the Bones in the Armature by direct selecting them in the scene outline panel.  I've done this also by going into edit mode for the Armature, then hitting A again, just to make sure I have all the bones selected...



Export, as before... Then in CC...

You don't need anything selected during export, unless you are specifically using the "export selected" option.

Ok...  

For anyone else watching, typically when you export objects from Blender you want to select "Selected Objects" (only) during export, otherwise every object in your scene will be exported. So, for instance, you're building a set in Blender and you've got layers with a bunch of meshes and objects you don't want to be part of the set when you export it... Typically you export only the selected objects for transfer to iClone via 3DX.  This has been my standard workflow for awhile.

CC changes all that, apparently.   All my attempts to follow this regular practice of exporting only selected objects from Blender has caused read errors on import in CC2.1.  Missing meshes and textures and bone - etc... 

So Rampa is correct... Don't select anything when you export your customized characters for CC... (There's a Reallusion tutorial that says you SHOULD do this... but it's for CC 1.5...  There's been a new version of Blender since then, so "expect delays." )  It's a good idea to clear your file of unwanted objects.  I'll explain:

When - after a long session of making clothing for your characters - you are ready to export finished assets back to CC it is a good idea to start with a clean .blend file.  Meaning: export out only the final clothing meshes you want to use from your working/project file, import those into a virgin .blend file, import the target base mesh you are binding your clothes to, perform the cloth-binding workflow from scratch, then export.  

Also... Just a note... CC wants you to have only ONE "shoes" or "gloves"  ... So, if, like me, you exported your shoes/boots as separate items (thinking that having them as a single object might interfere with the weight-transfer / cloth binding process) - you'll get an error during CC import.   Just leave your shoes/boots as a single object after you apply your mirror modifier.  If you have already separated your shoes/boots with CTRL P (to separate the meshes in edit mode), just CTRL J (Join) to make them a single object before you export everything.

Thanks again, Rampa!

Also, if you don't want to export your lights and camera, you can select just the object types you want exported. You only need mesh and armature. Shift-click to select more than one.