What model are you working on? did you unlock the file?
works for me
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LTB_TO_LTA Converter v2.41
By: Drigien
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Trying to Open: PV-Bazooka.LTB as a model
Success... Continuing
Fview-hand2 sub1: 4 2
Fview-arm2 sub1: 3 5
RPG_7_1st_person001 sub1: 1 1
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Reading in Bones: ...
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Reading in Weight Sets: ...
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Reading in Child Models: ...
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Reading in Animations: ...
idle_0
fire
prefire
postfire
run
select
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Reading in Sockets: ...
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Meshes: 3
Bones: 47
Animations: 6
Sockets: 1
ChildModels: 0
Weight Sets: 1
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Saving to LTA...
Saving...Sockets...Done
Saving...Mesh: 1 of 3 Lod: 1 of 1
Saving...Mesh: 2 of 3 Lod: 1 of 1
Saving...Mesh: 3 of 3 Lod: 1 of 1
Saving...Bones...Done
Saving...Animation: 1 of 6 Bone 47 of 47
Saving...Animation: 2 of 6 Bone 47 of 47
Saving...Animation: 3 of 6 Bone 47 of 47
Saving...Animation: 4 of 6 Bone 47 of 47
Saving...Animation: 5 of 6 Bone 47 of 47
Saving...Animation: 6 of 6 Bone 47 of 47
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Finished Decompiling: PV-Bazooka.lta