I think I see the issue. The name given in the plugin index and displayed via the "User Plugins" dialog is "Traditional<->Simplified Chinese Converter" where as the name I used in the plugin is "Chinese Text Conversion". I believe I changed the name at one point because the command shell processor and command line parser got annoyed when I used characters such as "<", "-", and ">".
I think the name in the plugin index may need to be changed.
For anyone writing plugins that may eventually use the command line interface:
- Avoid whitespace in the name
- Avoid using any character that might get interpreted by the shell or parser (e.g. <, >, - |, ! $, #, ?, /, \)