RFC functions

hi

when i am using rfc_ping like below the sy-subrc = 0.

CALL FUNCTION 'RFC_PING' DESTINATION dest_asia

EXCEPTIONS

communication_failure = 1

system_failure = 2

OTHERS = 3.

but, when i am using 'RFC_FUNCTION_SEARCH' to check for function module, it is throwing sy-subrc = 3 when the FM is present in the destination system. please help

CALL FUNCTION 'RFC_FUNCTION_SEARCH' DESTINATION dest_asia

EXPORTING

funcname = 'Z_MM_STOCK'

EXCEPTIONS

nothing_specified = 1

no_function_found = 2

OTHERS = 3.