diff -urN original/src/gwt/build.xml prefs/src/gwt/build.xml

--- original/src/gwt/build.xml	2011-09-30 09:02:51.000000000 -0700

+++ prefs/src/gwt/build.xml	2011-10-08 17:23:36.144811146 -0700

@@ -101,7 +101,7 @@

             <path refid="project.class.path"/>

          </classpath>

          <!-- add jvmarg -Xss16M or similar if you see a StackOverflowError -->

-         <jvmarg value="-Xmx512M"/>

+         <jvmarg value="-Xmx512M"/> <jvmarg value="-Djava.util.prefs.userRoot=/var/tmp/portage/sci-mathematics/rstudio-0.94.110/homedir"/>

          <arg value="-war"/>

          <arg value="www"/>

          <arg value="-localWorkers"/>

@@ -145,7 +145,7 @@

             <pathelement location="src"/>

             <path refid="project.class.path"/>

          </classpath>

-         <jvmarg value="-Xmx512M"/>

+         <jvmarg value="-Xmx512M"/> <jvmarg value="-Djava.util.prefs.userRoot=/var/tmp/portage/sci-mathematics/rstudio-0.94.110/homedir"/>

          <arg value="-war"/>

          <arg value="www"/>

          <arg value="-noserver"/>