Index: core/src/main/java/hudson/EnvVars.java
===================================================================
--- core/src/main/java/hudson/EnvVars.java	(revision 31286)
+++ core/src/main/java/hudson/EnvVars.java	(working copy)
@@ -151,10 +151,17 @@
     /**
      * Resolves environment variables against each other.
      */
-	public static void resolve(Map<String, String> env) {
-		for (Map.Entry<String,String> entry: env.entrySet()) {
-			entry.setValue(Util.replaceMacro(entry.getValue(), env));
+	public static EnvVars resolve(Map<String, String> env) {
+		EnvVars resolvedEnv = new EnvVars(env);
+		for (Map.Entry<String,String> entry: resolvedEnv.entrySet()) {
+			try {
+				entry.setValue(Util.replaceMacro(entry.getValue(), resolvedEnv));
+			} catch (UnsupportedOperationException uoe) {
+				System.out.println(uoe.getMessage() + " (" + entry.getValue() + ")");			
+			}
 		}
+		
+		return resolvedEnv;
 	}
 
     @Override
Index: core/src/main/java/hudson/model/AbstractBuild.java
===================================================================
--- core/src/main/java/hudson/model/AbstractBuild.java	(revision 31286)
+++ core/src/main/java/hudson/model/AbstractBuild.java	(working copy)
@@ -705,9 +705,7 @@
         for (EnvironmentContributingAction a : Util.filter(getActions(),EnvironmentContributingAction.class))
             a.buildEnvVars(this,env);
 
-        EnvVars.resolve(env);
-
-        return env;
+        return EnvVars.resolve(env);
     }
 
     public Calendar due() {