We were receiving this warning in both of our 11g RAC node's alert logs , after research i found that it is an ORACLE bug which is trying to warn you about ASMLIB not found in /opt !
WARNING::lib=/opt/oracle/extapi/64/asm err:9 rc:Directory does not exist
msgbuf=No such file or directory
it is a warning not an error, safely ignore it!
 Metalink Note. 727204.1