diff --git a/build/lib/jps/jps-builders.jar b/build/lib/jps/jps-builders.jar
index 05c199bfbb85..f937e00ed467 100644
Binary files a/build/lib/jps/jps-builders.jar and b/build/lib/jps/jps-builders.jar differ
diff --git a/build/scripts/utils.gant b/build/scripts/utils.gant
index e0cb06b9004c..d64c75f799d0 100644
--- a/build/scripts/utils.gant
+++ b/build/scripts/utils.gant
@@ -88,7 +88,7 @@ private String require(String key) {
     this[key]
   }
   catch (MissingPropertyException ignored) {
-    projectBuilder.error("Property $key is required")
+    projectBuilder.error("Property '$key' is required")
   }
 }
 
@@ -97,7 +97,7 @@ private String require(String key, String defaultValue) {
     this[key]
   }
   catch (MissingPropertyException ignored) {
-    projectBuilder.info("$key is not defined. Defaulting to $defaultValue")
+    projectBuilder.info("'$key' is not defined. Defaulting to '$defaultValue'")
     this[key] = defaultValue
   }
 }
@@ -112,8 +112,9 @@ binding.setVariable("requireProperty", {String key, String defaultValue = null -
 })
 
 binding.setVariable("guessHome", {
-  // Current file is supposed to be at build/scripts/release.gant path
-  new File(requireProperty("gant.file").substring("file:".length())).getParentFile().getParentFile().getParent()
+  // current file is supposed to be at build/scripts/*.gant path
+  String uri = requireProperty("gant.file")
+  new File(new URI(uri).getSchemeSpecificPart()).getParentFile().getParentFile().getParent()
 })
 
 binding.setVariable("loadProject", {
diff --git a/jps/standalone-builder/src/org/jetbrains/jps/idea/IdeaProjectLoader.groovy b/jps/standalone-builder/src/org/jetbrains/jps/idea/IdeaProjectLoader.groovy
index 627c9f821b99..d7e52c6d061f 100644
--- a/jps/standalone-builder/src/org/jetbrains/jps/idea/IdeaProjectLoader.groovy
+++ b/jps/standalone-builder/src/org/jetbrains/jps/idea/IdeaProjectLoader.groovy
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2014 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,21 +14,23 @@
  * limitations under the License.
  */
 package org.jetbrains.jps.idea
+
 /**
  * @author max
  */
 public class IdeaProjectLoader {
   public static String guessHome(Script script) {
-    File home = new File(script["gant.file"].substring("file:".length()))
+    String uri = script["gant.file"]
+    File home = new File(new URI(uri).getSchemeSpecificPart())
 
     while (home != null) {
-      if (home.isDirectory()) {
-        if (new File(home, ".idea").exists()) return home.getCanonicalPath()
+      if (home.isDirectory() && new File(home, ".idea").exists()) {
+        return home.getCanonicalPath()
       }
 
       home = home.getParentFile()
     }
 
-    return null
+    throw new IllegalArgumentException("Cannot guess project home from '" + uri + "'")
   }
 }