Variable Help

I can’t understand this… Can anyone explain it, or how to get around it?
I’ve got this on a movieclip:


onClipEvent(load){
    thisName = this._name
    thisPictureNumberArray = thisName.split("Container")
    thisPictureNumber = thisPictureNumberArray[1]
    //Picture Variables
    thisPictureTitle = _parent.titlesArray[thisPictureNumber]
    thisPictureDescription = _parent.descriptionsArray[thisPictureNumber]
    thisPicturePath = _parent.pathsArray[thisPictureNumber]
//******************If I trace(thispictureTitle) here, it works
    //Popup Window Variables
    winURL  =   "popup_2.html";
    winName = "Andrew Scott Photography";
    winWidth = 830;
    winHeight = 770;
    winToolbar = 0;
    winLocation = 0;
    winDirectories = 0;
    winStatus = 0;
    winMenuBar = 0;
    winScrollbars = 1;
    winResizable = 0;
}

//If clicked...
on(release) {
    //Send the Picture Info to the Popup
    //Open Popup
    getURL  ("javascript:var myWin; if(!myWin || myWin.closed){myWin = window.open('" +  winURL  +  "','"  +  winName  +  "','"  +  "width="  +  winWidth  +  ",height="  +  winHeight  +  ",toolbar="  +  winToolbar  +  ",location="  +  winLocation  +  ",directories="  +  winDirectories  +  ",status="  +  winStatus  +  ",menubar="  +  winMenuBar  +  ",scrollbars="  +  winScrollbars  +  ",resizable="  +  winResizable  +  ",top='+((screen.height/2)-("  +  h/2  +  "))+',left='+((screen.width/2)-("  +  w/2  +  "))+'"  +  "')}else{myWin.focus();};void(0);");
    //Check when the popup is opened.
    sendPicturreInfo = new LocalConnection();
    sendPicturreInfo.connectionOK = function(){
//******************If I trace(thispictureTitle) here, it doesn't work
        sendPicturreInfo.send("pictureInfo", "getinfo", "Title", "This is the first test picture.", "pictures/tort1.jpg");
    }
    sendPicturreInfo.connect("connectionTest");
}

(see the bits about trace(thispictureTitle))