Urgent Help - ALNUM in correlation function.

 Hello Friends,

I am facing issue, stated as below, please help.

Error Message : "Sub-argument number 1 of the "LB" argument (number 2) is invalid" for correlation function - I am trying to handle dymanic boundary in LB. Please let me know if any other info required.

web_reg_save_param("JSession_Id",
        "LB/ALNUM=JSESSIONID^^=",
        "RB=_SAP",
        LAST);