having a problem using a variable in a bursting control file

I have a problem trying to use a variable in a bursting control file.  I want to make the destination of my rtf file a variable as it changes from instance to instance.  When i hard code the value, it works. Listed below is the bursting control file.  The variable with the problem is ${CF_RTF_LOCATION}.  I have also shown a snipnet of the XML file which shows the variable.  You will notice two other variables in the control file, ${CF_MAIL_SERVER} and ${CF_MAIL_PORT}, which are working correctly.

bursting control file:

<xapi:requestset xmlns:xapi = "http://xmlns.oracle.com/oxp/xapi