Index: src/main/java/org/apache/maven/plugin/pmd/AbstractPmdReport.java
===================================================================
--- src/main/java/org/apache/maven/plugin/pmd/AbstractPmdReport.java	(revision 481675)
+++ src/main/java/org/apache/maven/plugin/pmd/AbstractPmdReport.java	(working copy)
@@ -56,7 +56,7 @@
      * @parameter expression="${project.reporting.outputDirectory}"
      * @required
      */
-    protected String outputDirectory;
+    protected File outputDirectory;
 
     /**
      * Site rendering component for generating the HTML report.
@@ -127,7 +127,7 @@
         String location = null;
         if ( linkXRef )
         {
-            String relativePath = PathTool.getRelativePath( outputDirectory, xrefLocation.getAbsolutePath() );
+            String relativePath = PathTool.getRelativePath( outputDirectory.getAbsolutePath(), xrefLocation.getAbsolutePath() );
             if ( StringUtils.isEmpty( relativePath ) )
             {
                 relativePath = ".";
@@ -244,6 +244,6 @@
      */
     protected String getOutputDirectory()
     {
-        return outputDirectory;
+        return outputDirectory.getAbsolutePath();
     }
 }