Create a new DTMManager in reset().

diff --git a/src/org/apache/xpath/XPathContext.java b/src/org/apache/xpath/XPathContext.java
index e3a0dd8..d6cd5c9 100644
--- a/src/org/apache/xpath/XPathContext.java
+++ b/src/org/apache/xpath/XPathContext.java
@@ -332,7 +332,11 @@
   /**
    * Reset for new run.
    */
-  public void reset(){}
+  public void reset()
+  {
+    m_dtmManager = DTMManager.newInstance(
+                   org.apache.xpath.objects.XMLStringFactoryImpl.getFactory());
+  }
 
   /** The current stylesheet locator. */
   SourceLocator[] m_saxLocations = new SourceLocator[RECURSIONLIMIT];