diff --git a/io_scene_psk_psa/__init__.py b/io_scene_psk_psa/__init__.py
index 0252bd3..44b2ddd 100644
--- a/io_scene_psk_psa/__init__.py
+++ b/io_scene_psk_psa/__init__.py
@@ -78,8 +78,10 @@ def register():
 
 
 def unregister():
-    del bpy.types.Scene.psa_export
     del bpy.types.Scene.psa_import
+    del bpy.types.Scene.psk_import
+    del bpy.types.Scene.psa_export
+    del bpy.types.Scene.psk_export
     bpy.types.TOPBAR_MT_file_export.remove(psk_export_menu_func)
     bpy.types.TOPBAR_MT_file_import.remove(psk_import_menu_func)
     bpy.types.TOPBAR_MT_file_export.remove(psa_export_menu_func)
diff --git a/io_scene_psk_psa/psa/builder.py b/io_scene_psk_psa/psa/builder.py
index 87549fb..a359096 100644
--- a/io_scene_psk_psa/psa/builder.py
+++ b/io_scene_psk_psa/psa/builder.py
@@ -55,7 +55,7 @@ class PsaBuilder(object):
         # Ensure that the exported hierarchy has a single root bone.
         root_bones = [x for x in bones if x.parent is None]
         if len(root_bones) > 1:
-            root_bone_names = [x.name for x in bones]
+            root_bone_names = [x.name for x in root_bones]
             raise RuntimeError('Exported bone hierarchy must have a single root bone.'
                                f'The bone hierarchy marked for export has {len(root_bones)} root bones: {root_bone_names}')
 
diff --git a/io_scene_psk_psa/psa/exporter.py b/io_scene_psk_psa/psa/exporter.py
index 6632111..470b8c9 100644
--- a/io_scene_psk_psa/psa/exporter.py
+++ b/io_scene_psk_psa/psa/exporter.py
@@ -140,8 +140,7 @@ class PsaExportOperator(Operator, ExportHelper):
 
         if pg.bone_filter_mode == 'BONE_GROUPS':
             rows = max(3, min(len(pg.bone_group_list), 10))
-            layout.template_list('PSX_UL_BoneGroupList', '', pg, 'bone_group_list', pg,
-                              'bone_group_list_index', rows=rows)
+            layout.template_list('PSX_UL_BoneGroupList', '', pg, 'bone_group_list', pg, 'bone_group_list_index', rows=rows)
 
     def is_action_for_armature(self, action):
         if len(action.fcurves) == 0:
diff --git a/io_scene_psk_psa/psa/importer.py b/io_scene_psk_psa/psa/importer.py
index be19140..4be3729 100644
--- a/io_scene_psk_psa/psa/importer.py
+++ b/io_scene_psk_psa/psa/importer.py
@@ -257,10 +257,10 @@ class PSA_UL_SequenceList(UIList):
     def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
         row = layout.row(align=True)
         split = row.split(align=True, factor=0.75)
-        action_col = split.row(align=True)
-        action_col.alignment = 'LEFT'
-        action_col.prop(item, 'is_selected', icon_only=True)
-        action_col.label(text=item.action_name)
+        column = split.row(align=True)
+        column.alignment = 'LEFT'
+        column.prop(item, 'is_selected', icon_only=True)
+        column.label(text=item.action_name)
 
     def draw_filter(self, context, layout):
         row = layout.row()
diff --git a/io_scene_psk_psa/psk/builder.py b/io_scene_psk_psa/psk/builder.py
index c715f39..44425cc 100644
--- a/io_scene_psk_psa/psk/builder.py
+++ b/io_scene_psk_psa/psk/builder.py
@@ -91,7 +91,7 @@ class PskBuilder(object):
             print('root bones')
             print(root_bones)
             if len(root_bones) > 1:
-                root_bone_names = [x.name for x in bones]
+                root_bone_names = [x.name for x in root_bones]
                 raise RuntimeError('Exported bone hierarchy must have a single root bone.'
                                    f'The bone hierarchy marked for export has {len(root_bones)} root bones: {root_bone_names}')