Index: src/java/org/apache/poi/poifs/filesystem/NDocumentInputStream.java
===================================================================
--- src/java/org/apache/poi/poifs/filesystem/NDocumentInputStream.java	(revision 1156562)
+++ src/java/org/apache/poi/poifs/filesystem/NDocumentInputStream.java	(working copy)
@@ -291,7 +291,7 @@
 		checkAvaliable(SIZE_SHORT);
       byte[] data = new byte[SIZE_SHORT];
       readFully(data, 0, SIZE_SHORT);
-      return LittleEndian.getShort(data);
+      return LittleEndian.getUShort(data);
 	}
 
    @Override
Index: src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java
===================================================================
--- src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java	(revision 1156562)
+++ src/testcases/org/apache/poi/hssf/usermodel/TestBugs.java	(working copy)
@@ -2146,7 +2146,7 @@
     /**
      * Large row numbers
      */
-    public void DISABLEDtest51535() throws Exception {
+    public void test51535() throws Exception {
        byte[] data = HSSFITestDataProvider.instance.getTestDataFileContent("51535.xls");
        
        HSSFWorkbook wbPOIFS = new HSSFWorkbook(new POIFSFileSystem(