RFC connection error

Hi,

When i am trying to display datasource in source system on BI system, it is showing error message:

Error when opening an RFC connection (CP IC-CALL: 'ThSAPOCMINIT' : cmRc=27 thRc=2)

Message no. RSAR051

Please help me this issue. RFC connection and Source system checking is working fine. RFC registration and every thing fine, still i am getting this error.

Thanks & regards,

Surendra