I saw in both log files of the AdminServer and soa_server1, one small line:
<Native IO Disabled. Using Java IO.>
This line implies that the system will use Java code instead of O/S specific libraries for executing I/O function.
This can be fixed by setting the correct dynamic Libraries; LD_LIBRARY_PATH.
Make sure you set the LD_LIBRARY_PATH in your start scripts of the Admin and managed servers.
Add this in the start scripts:
This will result in the following line on the log :-)
<Native IO Enabled.>