Could not lock User prefs

I’m running MEGAN 5.10.0 on RHEL 6 under xvfb-run and a command script for taxonomy reporting from a diamond m8 output. Occasionally I get pages of the below spam. It doesn’t seem to adversely affect program function (it can go on for hours). My home directory is on an NFS mount.

Aug 07, 2015 8:12:17 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock User prefs.  Unix error code 37.
Aug 07, 2015 8:12:17 PM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Aug 07, 2015 8:12:47 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock User prefs.  Unix error code 37.
Aug 07, 2015 8:12:47 PM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Aug 07, 2015 8:13:17 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock User prefs.  Unix error code 37.
Aug 07, 2015 8:13:17 PM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Aug 07, 2015 8:13:47 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock User prefs.  Unix error code 37.
Aug 07, 2015 8:13:47 PM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Aug 07, 2015 8:14:17 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock User prefs.  Unix error code 37.
Aug 07, 2015 8:14:17 PM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Aug 07, 2015 8:14:47 PM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode

My ~/.java/com/install4j/installations/prefs.xml exists and is readable/writable.

looks horrible, but shouldn’t affect the program…