Hello at all!

In my scene I made a chair on wich a letter lays with an animated Text. Surrounding I made a sphere for the Environment. For the Text animation I rendered with Maya software the letter Texture for 100 frames.
This 100 frames I used in my scene as an image sequence for my Letter material.
When I render the scene with maya software, the Text animation is visible. But when I render with Mental ray, the Letter is black and the render Diagnostic tells me that the node file(texture) is missing.
But it is still there.
whats going wrong?
I tried to change the frame setting from my letter animation NAME.tga.001 to NAME.001.tga, but the problem is still there.
I deleted the shader and made a new...nothing shanged!
Please help me in this case, I really tried everything to fix it out myself. The Timeline setting is OK. Start and end from the texture image sequence are at the right place in the scene timeline.
CONTEXT:
a poly plane with a lambert shader
for the material I used a texture, image sequence turned on.
maya software test rendering runs Ok!
Mental Ray can´t render the Image sequence!
The letter is black