BPEL Workflow

 Hi Team,
   We are launching BPEL using Oracle PL/SQL,

  Launching BPEL in the form of XML tags , sometimes workflow triggering correctly,

 sometime its going into exceptions and not launching workflow properly, please suggest is there any way to come out of this to lunch workflow without any issues.

 we are using below mentioned technology for launching BPEL.


soap_request := NULL;
         soap_request :=
            '<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
                           <soap:Header/>
                           <soap:Body xmlns:ns1="l">
                           <ns1:ProductWorkflowApprovalRequest>
                           <ns1:ProductList>';
         DBMS_LOB.createtemporary (soap_prod, TRUE);
         DBMS_LOB.WRITE (soap_prod, LENGTH (soap_request), 1, soap_request);