Hello, I've created a simple tail mesh as an accessory, I followed the tutorial, Although I do have some questions, It gives me an error when trying to export the mesh "Seams" something about the seams need to be split? I copied the comments from a bracelet, I am not sure where to go from there, it's a tail and I doubt it needs morphs. I've attached a picture of it. I use a basic cylinder. I made LOD's But The tutorial is confusing and they don't show up,the tail doesn't show up at all. I think its because I get the error when trying to export he mesh? Help?

Go to the Milkshape Tools menu, click 'Model Cleaner', No to the first popup and Okay to the second.

The problem is the UV mapping - you have the texture wrapped around the mesh with a seam along one side, and on the seam you have one vertex with two different UV coordinates which needs to be split into two vertices at the same location. The tool above does this automatically.

Ah! It fixed it, But I can't seem to get the mesh to come up in the CTU, The tutorial is confusing though...

What tutorial are you using, or exactly what steps are you going through? CTU can be tricky, these are the basic steps with a new mesh:

Select a similar item, in this case an accessory with a mesh, like a bracelet, watch, or earrings
In the Designs tab add at least one new design
In the Meshes tab, import your meshes, give it a new unique mesh name, click Commit
Save as a new package
Open the package you just saved, and in the Designs tab import your textures and set up presets with your colors, patterns, stencils if any, etc. The new mesh should be visible in the preview.
Save when done.