Solution : https://service.sap.com/sap/support/notes/620633 (SAP Service marketplace login required)
Summary : 
      In the SAP Exchange Infrastructure, qRFC inbound queues are observed hanging in the RUNNING status. This issue arises due to a defect in the XI application, which prevents the processing of qRFC requests. Additionally, the RFC destination, AI_RUNTIME_JCOSERVER, is unregistered. This situation is identifiable in SM04, where users initiating the QIN scheduler are listed with an "RFC" type. For resolution, refer to SAP Note 615024.
Key words : 
sap exchange infrastructure hang, qrfc inbound queues, qrfc requests, inbound queue, running status, qin scheduler, mapping tool, sxms_async_exec reason, prerequisites due, xi application
Related Notes : 
       
| 1118297 | XI runtime: QRFC processing of messages | 
| 615024 | Mapping tool looses values sometimes |