Solution : https://service.sap.com/sap/support/notes/845801 (SAP Service marketplace login required)
Key words :
portal sp2 patch 30, default language configured, symptom jcoclientservice fails, jcoclinetservice fails, portal sp11, requested language, returned error, terms jco_error_program, jco_error_logon_failure reason, backend system
Related Notes :
| 808581 | Central Note - Installing Portal Patch 30 for EP 6.0 |
| 805233 | Central Note - SP Stack 11 - SAP NW 04 EP 6.0 on Web AS 6.4 |