The persistent file store "_WLS_DefaultServer" is forced to use buffered I/O and so may have significantly degraded performance. Either the OS/hardware environment does not support the chosen write policy or the native wlfileio library is missing. See store open log messages for the requested and final write policies. See the documentation on store synchronous write policy configuration for advice.
See this post it fixed it for me:http://javaosdev.blogspot.com/2011/10/weblogic-defeating-unable-to-load.html