Actually let's use one we know will stick around.
diff --git a/releng/org.eclipse.amp.releng/build.properties b/releng/org.eclipse.amp.releng/build.properties
index 39ced9a..2450af3 100755
--- a/releng/org.eclipse.amp.releng/build.properties
+++ b/releng/org.eclipse.amp.releng/build.properties
@@ -39,7 +39,7 @@
 http://metaabm.org/downloads/repast-score.zip
 
 repositoryURLs=http://download.itemis.com/updates/milestones,\
-http://download.eclipse.org/tools/orbit/downloads/drops/S20100519200754/updateSite,\
+http://download.eclipse.org/tools/orbit/downloads/drops/R20100519200754/updateSite,\
 http://download.eclipse.org/modeling/tmf/xtext/downloads/drops/1.0.0/S201005041135/tmf-xtext-Update-1.0.0M7.zip,\
 http://download.eclipse.org/modeling/m2t/xpand/downloads/drops/1.0.0/S201003150948/m2t-xpand-Update-1.0.0M6.zip,\
 http://download.eclipse.org/modeling/emft/mwe/downloads/drops/0.7.2/R200908120417/emft-mwe-Update-incubation-0.7.2.zip,\