Adding the values of 3 dynamic text boxes

I have 3 dynamic text boxes on the main movies stage that are getting their values from an externally loaded swf. If statements within the external movie loads the values from an xml file depending on which action is selected by the user. Now I have a fourth text box that needs to gather all the values that are loaded in the other 3 and add them together…placing zero if nothing is loaded. I have done various code tests…I get either NAN or _level0.total …total is the instance name of one of the boxes, I am trying to access. Anyone know what I am doing wrong or where to turn to figure it out.

any help would be appreciated

thanks