Invalid file type

[DeGraphics-Studios]

While using the addon on 2.78, I tried importing a model made by a specific person and it said the file type was invalid. I have tried importing models made by the same person earlier and they imported just fine. I have no idea what the problem is.

[lordscales91]

Sorry but this project is currently not being maintained here. Fortunately there is a very good fork in active development. Check this #53 for more info.

PD: About your specific problem, I think it may be a bad signature issue. Check the following link to solve it: http://fav.me/d923pu1

[Hogarth-MMD]

@powroupi is the current developer of mmd_tools.
You can find lots of great bug fixes and additional features in the version of mmd_tools by @powroupi:
https://github.com/powroupi/blender_mmd_tools/archive/dev_test.zip
https://github.com/powroupi/blender_mmd_tools
https://github.com/powroupi/blender_mmd_tools/issues