It is a regression.

The issue is reproduced with NetBeans IDE 6.1 
I use NetBeans IDE 6.1 200801170000 from 
  http://bits.netbeans.org/netbeans/trunk/nightly/latest
and JavaFX Script plugin 2008-01-17_02-01-45.zip from release60 brunch

Steps to reproduce:

- Create  a JavaFX Script file:
-------------------------------------
var a = 10;
a++;
-------------------------------------
- Enable the 'Error Detection and Syntax Highligting'

The exception pops up:

java.lang.IllegalArgumentException: Parameter file was not normalized. Was Documents and Settings\andromeda\My
Documents\NetBeansProjects\test\02\JavaFXApplication3\src\javafxapplication3\Main.fx instead of C:\Program
Files\NetBeans 6.1\Documents and Settings\andromeda\My
Documents\NetBeansProjects\test\02\JavaFXApplication3\src\javafxapplication3\Main.fx
	at org.openide.filesystems.FileUtil.toFileObject(FileUtil.java:597)
	at org.netbeans.modules.javafx.parser.FXParser.uriToFileObject(FXParser.java:539)
	at org.netbeans.modules.javafx.parser.FXParser.fillResultsForGoTo(FXParser.java:487)