compilation error in Variable declaration

If you see the following exception and unable to figure out what is the reason. Don't panic. Just relax and look for a syntax error among the variable declarations in the last set of files you edited after which this error started coming.
Flex3 compiler and Flex3 Builder is unable to figure out such syntax errors:
http://bugs.adobe.com/jira/browse/SDK-15030

[mxmlc] Error: macromedia.asc.parser.MetaDataEvaluator$KeyValuePair

    [mxmlc] java.lang.ClassCastException: macromedia.asc.parser.MetaDataEvaluator$KeyValuePair
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.SetExpressionNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MemberExpressionNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.ListNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.ExpressionStatementNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.ClassDefinitionNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.StatementListNode.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.MetaDataEvaluator.evaluate(Unknown Source)
    [mxmlc]     at macromedia.asc.parser.ProgramNode.evaluate(Unknown Source)
    [mxmlc]     at flex2.compiler.as3.Compiler.analyze3(Compiler.java:531)
    [mxmlc]     at flex2.compiler.mxml.InterfaceCompiler.analyze3(InterfaceCompiler.java:378)

Some examples where the above exception will be reported by mxmlc are :

public var myButton = String = null;
public var myButton : String = null; = null;

Location of Flash SharedObject (cookie)

Shared objects are stored in .sol files located in the Flash player directory of the user's profile:

* Windows Vista : C:\Users\{user-name}\AppData\Roaming\Macromedia\Flash Player\
* Windows XP : "C:/Documents and Settings/{user-name}/Application Data/Macromedia/Flash Player"
* Linux : /home/{user-name}/.macromedia/Flash_Player/
* Mac : /Users/{user-name}/Library/Preferences/Macromedia/Flash Player/

Flex4 - Gumbo beta released

Overview:

http://opensource.adobe.com/wiki/display/flexsdk/Gumbo


Download:

http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4

DataGrid - Extracting edited Value from DataGridEvent

    private function saveValue(event:DataGridEvent) : void
    {
        if(event.reason == DataGridEventReason.CANCELLED)    
           return;
        var newValue : String = TextInput(event.currentTarget.itemEditorInstance).text;
        var prevCellValue : String = myDataGrid.selectedItem[event.dataField];
       
        if( prevCellValue == newValue)
           return;
        Alert.show("New value :: "+newValue);
    }

    ...
    ...

 <mx:DataGrid id="myDataGrid" width="100%" dataProvider="{defCreativeVals}" editable="true" itemEditEnd="{saveValue(event)}">
 <mx:columns>
     <mx:DataGridColumn headerText="Column" id="colColumn" editable="false" dataField="name"/>
     <mx:DataGridColumn headerText="Value" id="colValue" editable="true" dataField="value" />
 </mx:columns>
 </mx:DataGrid>