500 Internal Server Error

incompatible character encodings: UTF-8 and ASCII-8BIT
(Encoding::CompatibilityError)

(plugin/makerss.rb):384:in `makerss_body'
(plugin/makerss.rb):238:in `block (3 levels) in makerss_update'
(plugin/makerss.rb):237:in `each'
(plugin/makerss.rb):237:in `block (2 levels) in makerss_update'
(plugin/makerss.rb):235:in `each'
(plugin/makerss.rb):235:in `each_with_index'
(plugin/makerss.rb):235:in `block in makerss_update'
/usr/lib/ruby/1.9.1/pstore.rb:332:in `block (2 levels) in transaction'
/usr/lib/ruby/1.9.1/pstore.rb:331:in `catch'
/usr/lib/ruby/1.9.1/pstore.rb:331:in `block in transaction'
/usr/lib/ruby/1.9.1/pstore.rb:362:in `synchronize'
/usr/lib/ruby/1.9.1/pstore.rb:322:in `transaction'
/home/hsbt/dev/tdiary-core/misc/lib/compatible.rb:46:in `transaction'
(plugin/makerss.rb):187:in `makerss_update'
(plugin/makerss.rb):401:in `block (2 levels) in load_plugin'
/home/hsbt/dev/tdiary-core/tdiary.rb:842:in `call'
/home/hsbt/dev/tdiary-core/tdiary.rb:842:in `block in update_proc'
/home/hsbt/dev/tdiary-core/tdiary.rb:841:in `each'
/home/hsbt/dev/tdiary-core/tdiary.rb:841:in `update_proc'
/home/hsbt/dev/tdiary-core/tdiary.rb:1542:in `block in do_eval_rhtml'
/home/hsbt/dev/tdiary-core/tdiary.rb:1542:in `instance_eval'
/home/hsbt/dev/tdiary-core/tdiary.rb:1542:in `do_eval_rhtml'
/home/hsbt/dev/tdiary-core/tdiary.rb:1097:in `eval_rhtml'
/home/hsbt/dev/tdiary-core/tdiary/dispatcher.rb:157:in `run'
/home/hsbt/dev/tdiary-core/tdiary/dispatcher.rb:212:in `dispatch_cgi'
/var/www/diary/update.rb:26:in `<main>'