The exception is:

Caused by: java.io.FileNotFoundException: /scratch/yungchoi/weblogic/sr2_S706b18/bea/buildout/functional/beangen/tempdir/test-descriptor.xml.tmp (No such file or directory)
              at java.io.FileOutputStream.open(Native Method)
              at java.io.FileOutputStream.<init>(FileOutputStream.java:203)
              at java.io.FileOutputStream.<init>(FileOutputStream.java:95)
              ... 26 more

The problem is that 'tempdir' does not exist.
This failure does not occur when JDK7u6b12 is used
It does occur when JDK7u6b18 is used.
Don't know about intervening versions.