This looks like a question to ask of the plug in developer.
ReactorLanguage( "LanguageShortCode" )
Is not a built in FileMaker function.
the thing is i wonna have a calendar looking for a learning file or so ,
this looked easy but .... .expensive :p
Here's a free demo file of a simple calendar solution I created: http://www.4shared.com/file/6UAOV_RZ/Calendar.html
If you don't have filemaker 11, you'll need to change it a bit but it can be gotten to work without too much trouble.
No plug in needed.