When I run Duke Nukem with voxel models, they load a long time - sometimes over 2 minutes.
Short answer: Use lower resolution models.
Long answer: Load times are long for voxel models because my code tries to combine coplanar surfaces of neighboring cubes to reduce polygon count. In doing so, it must allocate each little piece onto a single skin - basically a memory allocator in 2 dimensions. It's a tricky problem with no perfect solution. My allocator is pretty good at fitting things, but it it's not optimized well for large models. When writing it, I tested it mainly with the small voxel models that come with Shadow Warrior.
in certain voxels frames, half of models particles become broken.
A screenshot would be helpful. First you should figure out whether it's a problem with POLY2VOX or JF*. That's easy - look at each .KVX frame in SLAB6. If all looks is good there, it could be a problem with my skin allocator - which could possibly be fixed by using a lower resolution.