m3g format validation

When loading my model.m3g file, Loader throws IOExc开发者_运维问答eption, indicating my .m3g is not valid, but it doesn't tell where or which object is invalid.

Viewers floating around on the web can't open it either; nor do they prompt any specific error message.

I know the file is mostly good because I can manually parse the file and know each Mesh, Appearance, World, Camera, Background object are valid.

How can I diagnose further?

IOException comes from the following 2 reasons: 1. if name, or any resource referenced from it, cannot be resolved or accessed 2. if the data in name, or in any resource referenced from it, is not in accordance with the M3G and PNG file format specifications.

for "File Format for Mobile 3D Graphics API" refer the following link: http://www.developer.nokia.com/document/Java_Developers_Library_v2/GUID-07274ED2-697C-4987-ABE9-7FFE82605633/file-format.html