Not able to pass the variables in design studio

Hi,

I am not able pass the variables in design studio using the drop down box on apply script.

I am able to pass one variable ZDB_FISCPER but the variable ZDB_FISCPER_LY is not passed correctly.

basically i am trying to pass selection fiscalperiod  to ZDB_FISCPER (for ex. 2008005) and lastyear same fiscal period to ZDB_FISCPER_LY(2007005)

I have initialized the variables fiscper &fiscper1 as global variables.

Following is my script on apply for dropdown box:

ex: dropdown fiscal period = V32008005 based on this i have written the script and it is giving correct values as checked in text box (for ex like 2008005)

var range = DROPDOWN_1.getSelectedValue();

var fyear = Convert.subString(range,2,6);

var fmonth =  Convert.subString(range,6,10);

var fyear1 =  Convert.stringToInt(fyear)-1;

var fyear2 = "" + fyear1;

fiscper = fyear + fmonth;

fiscper1 = fyear2 + fmonth;

SALES_MNTHLY.setVariableValue("ZDB_FISCPER", fiscper);

SALES_MNTHLY.setVariableValueExt("ZDB_FISCPER_LY",fiscper1)

the last script statement is not working properly.

Please help.