What 3D program are you using? This may help those reading this, as it could be a problem from within your program, some applications can be found to have bad animation export. However as you said you're using a 3ds model, this could be your problem, as DBP has been updated over the years, support for the 3ds file format was dropped and became archaic, they still work, but they can have their errors. Try using .x instead of .3ds and see what happen. (If you program doesn't export .x then there are .3ds to .x converters.
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