Solution : https://service.sap.com/sap/support/notes/628466 (SAP Service marketplace login required)
Key words :
<%irj_home%>\web-inf\plugins\portal\resources\<%mycomponent%>\, symptom jsp files, existing business package, jsp pages contained, compilation reason, import tool, generated classes, work folder, recompiled, prerequisites
Related Notes :
| 793582 | Central Note - Installing Portal Patch 28 for EP 6.0 SP2 |
| 588665 | Composite SAP Note for business packages |