rails webpacker:install　が出来ない

MacBook-Pro sample_app % rails webpacker:install を実行すると
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils/version.rb:4: warning: already initialized constant FileUtils::VERSION
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:105: warning: previous definition of VERSION was here
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils.rb:1267: warning: already initialized constant FileUtils::Entry_::S_IF_DOOR
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:1284: warning: previous definition of S_IF_DOOR was here
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils.rb:1540: warning: already initialized constant FileUtils::Entry_::DIRECTORY_TERM
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:1577: warning: previous definition of DIRECTORY_TERM was here
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils.rb:1595: warning: already initialized constant FileUtils::OPT_TABLE
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:1635: warning: previous definition of OPT_TABLE was here
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils.rb:1649: warning: already initialized constant FileUtils::LOW_METHODS
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:1694: warning: previous definition of LOW_METHODS was here
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/2.6.0/fileutils.rb:1656: warning: already initialized constant FileUtils::METHODS
/Users/eitro10/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/fileutils-1.5.0/lib/fileutils.rb:1701: warning: previous definition of METHODS was here
sh: -c: line 0: syntax error near unexpected token ('
sh: -c: line 0:/Users/eitro10/.rbenv/versions/2.6.5/bin/ruby ./bin/rails app:template LOCATION=/Users/eitro10/Dropbox/My Mac (吉岡　慧人のMacBook Pro)/Desktop/private/sample_app/vendor/bundle/ruby/2.6.0/gems/webpacker-5.2.1/lib/install/template.rb'

上記のエラーが発生します。
アドバイスをお願いします。