If you run the attached Jelly script against JIRA (no other setup, preparation necessary) the user simply gets a blank page back. The log has the following stack trace:

2008-09-19 13:45:57,756 http-8090-Processor4 [webwork.dispatcher.ServletDispatcher] Could not execute action
org.apache.commons.jexl.parser.TokenMgrError: Lexical error at line 1, column 10. Encountered: "\u00f3" (243), after : ""
at org.apache.commons.jexl.parser.ParserTokenManager.getNextToken(ParserTokenManager.java:756)
at org.apache.commons.jexl.parser.Parser.jj_scan_token(Parser.java:3165)

There is a problem in the user script but JIRA should handle the error better.

JIRA is currently using commons-jexl 1.0. It appears that commons-jexl 1.1 was released Sept 9, 2006. On a whim I tried running JIRA against jexl 1.1. The same error occurred but this time JIRA displayed a nice error message to the user that helped me pinpoint the problem.