diff --git a/lib/redmine_dmsf/webdav/base_resource.rb b/lib/redmine_dmsf/webdav/base_resource.rb
index d43e1624..00b78e58 100644
--- a/lib/redmine_dmsf/webdav/base_resource.rb
+++ b/lib/redmine_dmsf/webdav/base_resource.rb
@@ -120,6 +120,7 @@ module RedmineDmsf
           i = 1
           project_names = Setting.plugin_redmine_dmsf['dmsf_webdav_use_project_names']
           while true
+            prj = nil
             pinfo = @path.split('/').drop(i)
             if pinfo.length > 0
               if project_names
@@ -137,7 +138,6 @@ module RedmineDmsf
             break unless prj
             i = i + 1
             @project = prj
-            prj = nil
           end
         end
         @project
@@ -148,6 +148,7 @@ module RedmineDmsf
         i = 1
         project_names = Setting.plugin_redmine_dmsf['dmsf_webdav_use_project_names']
         while true
+          prj = nil
           pinfo = @path.split('/').drop(i)
           if pinfo.length > 0
             if project_names
@@ -164,9 +165,7 @@ module RedmineDmsf
           end
           return '/' + @path.split('/').drop(i).join('/') unless prj
           i = i + 1
-          prj = nil
         end
-        puts ">>> Error: #{@path}"
       end
 
       def path_prefix
diff --git a/lib/redmine_dmsf/webdav/dmsf_resource.rb b/lib/redmine_dmsf/webdav/dmsf_resource.rb
index e1585aac..5c7efeaf 100644
--- a/lib/redmine_dmsf/webdav/dmsf_resource.rb
+++ b/lib/redmine_dmsf/webdav/dmsf_resource.rb
@@ -94,7 +94,7 @@ module RedmineDmsf
       def folder
         unless @folder
           @folder = DmsfFolder.visible.where(project_id: project.id, title: basename,
-            dmsf_folder_id: parent.folder ? parent.folder.id : nil).first if project
+            dmsf_folder_id: parent&.folder&.id).first if project
         end
         @folder
       end
@@ -102,7 +102,7 @@ module RedmineDmsf
       # Check if the current entity exists as a file (DmsfFile), and returns corresponding object if found (nil otherwise)
       def file
         unless @file
-          @file = DmsfFile.find_file_by_name(project, parent.folder, basename) if project
+          @file = DmsfFile.find_file_by_name(project, parent&.folder, basename) if project
         end
         @file
       end
@@ -111,7 +111,7 @@ module RedmineDmsf
         unless @subproject
           if Setting.plugin_redmine_dmsf['dmsf_webdav_use_project_names']
             if basename =~ / (\d+)$/
-              @subproject = Project.visible.where(id: $1, parent_id: parent_project.id).first
+              @subproject = Project.visible.where(id: $1, parent_id: parent_project&.id).first
               if @subproject
                 # Check again whether it's really the project and not a folder with a number as a suffix
                 @subproject = nil unless basename =~ /^#{@subproject.name}/