First of all, do your models have UV-maps? If so, do your textures use those UV-maps (rather than another system, such as generated UV coordinates)? To the best of my knowledge, YABEE only exports UV-mapped textures.
Material colours should work; when viewing in PView, did you turn on PView’s light? I believe that in Panda, material colours only show up when lit. (If I’m not much mistaken, when viewing a model in PView, you can toggle the light using the “l” key.)
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Oh, one more thing: there may be a conflict between your version of Blender and YABEE.
From what I gather, Blender’s API sometimes changes between releases, meaning that a given version of YABEE won’t necessarily work with all versions of Blender. Looking at the YABEE thread, I see that YABEE version 13.1 is intended for Blender version 2.66–have you tried using that version of Blender?