500 Internal Server Error

cannot load such file -- rd/rdfmt (LoadError)

<internal:/usr/local/rvm/rubies/ruby-3.0.2/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/usr/local/rvm/rubies/ruby-3.0.2/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary/rd_style.rb:19:in `<top (required)>'
<internal:/usr/local/rvm/rubies/ruby-3.0.2/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/usr/local/rvm/rubies/ruby-3.0.2/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:434:in `block in load_styles'
<internal:dir>:134:in `glob'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:433:in `load_styles'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary/defaultio.rb:142:in `initialize'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:1067:in `new'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:1067:in `initialize'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:1694:in `initialize'
/virtual/tmaeda/public_html/tdiary-3.0.1/tdiary.rb:1961:in `initialize'
index.rb:63:in `new'
index.rb:63:in `<main>'