There could be an overlapping material zone which is conflicting with the default material zone.  I get this sometimes.  Sorry, but I don't know of a solution.

This is a stupid question, but is it UV mapped?

Yep.

I'm stumped. I don't think I have ever had this problem before. Usually I get problems when I don't UV map.

Sorry, I have nothing to contribute.

What are the names of your materials?

Collar 

Sleeves

Cuff

button

I was wondering if you had any names that included spaces. Those look OK.

Can you post a screen shot of your UV map?

2

OK still not seeing anything wrong :)

Let's try a screen shot of your material room shader tree set up.

Forget it Phil. I think I'm just going to start over and see what happens with that one.

Thanks for your help though.

export the shirt ,texture back out of poser and see if the texture renders in ya modeling app.

if it does then ya poser settings are off.

it's always that one thing we didn't do just right.

I had this exact problem trying to re-texture a free 3DS model I'd downloaded last week.  Did some research, and it appeared that the normals in the original model might have been facing the wrong way i.e. backwards, as the texture which I thought I'd applied appeared on the back of the model, and was thus invisible from the front.  I'm no expert, so shoot me down if you want, but it might help.