Well, I downloaded the Halo 2 Elite Biped tags, uploaded by Delta4907, and when I go to select one of them, a window pops up saying:

Not all the selected tags could be added to the palette:
You selected one or more files that couldn't be loaded correctly.

Contact your nearest Bungie programmer for assistance.

And the debug said:

04.23.12 14:29:40 file_open('tags\delta4907\characters\h2elite\h2elite.gbxmodel') error 0x00000003 'The system cannot find the path specified. '
04.23.12 14:29:40 couldn't open gbxmodel tag 'h2elite.gbxmodel'.
04.23.12 14:29:40 file_open('tags\delta4907\characters\h2elite\h2elite.model_animations') error 0x00000003 'The system cannot find the path specified. '
04.23.12 14:29:40 couldn't open model_animations tag 'h2elite.model_animations'.
04.23.12 14:29:40 file_open('tags\delta4907\characters\h2elite\h2elite.model_collision_geometry') error 0x00000003 'The system cannot find the path specified. '
04.23.12 14:29:40 couldn't open model_collision_geometry tag 'h2elite.model_collision_geometry'.
04.23.12 14:29:40 file_open('tags\delta4907\characters\h2elite\shaders\shield plasma.shader_transparent_plasma') error 0x00000003 'The system cannot find the path specified. '
04.23.12 14:29:40 couldn't open shader_transparent_plasma tag 'shield plasma.shader_transparent_plasma'.
04.23.12 14:29:40 file_open('tags\characters\elite\elite melee.damage_effect') error 0x00000002 'The system cannot find the file specified. '
04.23.12 14:29:40 couldn't open damage_effect tag 'elite melee.damage_effect'.
04.23.12 14:29:40 file_open('tags\sound\dialog\elite\conditional\elite.dialogue') error 0x00000003 'The system cannot find the path specified. '
04.23.12 14:29:40 couldn't open dialogue tag 'elite.dialogue'.
04.23.12 14:29:40 file_open('tags\globals\elite.material_effects') error 0x00000002 'The system cannot find the file specified. '
04.23.12 14:29:40 couldn't open material_effects tag 'elite.material_effects'.
04.23.12 14:29:40 failed to load biped tag 'tags\delta4907\characters\h2elite\h2elite'

Could anyone tell me how to fix this?

Yeah, the main reason I picked Delta was because they came with Councilors and Guardsmen. But I'll get the Halo 2 v2 pack by HDoan. I'll get more with that, I guess. Thanks.