web_reg_save_param issue

I get an error message saying 'No match found for the requested parameter "Test"'. The web_reg_save_param I've written is:

web_reg_save_param("Test",
"LB=arrData[0][1][0] = new Array('",
"RB='",
LAST);

web_custom_request("xxxx.action_x", "URL=","Method=","Resource=0","RecContentType=text/html","Referer=","Snapshot=","Mode=HTML","EncType=application/x-www-form-urlencoded; charset=UTF-8",
//"Body=hdnMode=ADDTOITN&dnData=804O320xxxxxx10/03/201022:501003/201020:403803I320xxxxxx12/03/201023:3512/03/201021:20/1 | ^ ~,LAST);

"Body=hdnMode=ADDTOITN&dnData={Test}/1 | ^ ~,LAST);

I have located the value in the generation log,

arrData[0][1][0] = new Array('804O320xxxxxx10/03/201022:5010/03/201020:403803I320xxxxxx12/03/201023:3512/03/201021:20/1', null);

What seems to be the error here?

Thanks,