diff -ur jna-3.0.4-svn630/src/com/sun/jna/Structure.java jna-3.0.4-svn630.orig/src/com/sun/jna/Structure.java
--- jna-3.0.4-svn630/src/com/sun/jna/Structure.java	2008-09-05 21:49:16.000000000 -0400
+++ jna-3.0.4-svn630.orig/src/com/sun/jna/Structure.java	2008-09-06 17:43:34.000000000 -0400
@@ -612,28 +612,28 @@
 
         // Set the value at the offset according to its type
         if (nativeType == boolean.class || nativeType == Boolean.class) {
-            memory.setInt(offset, Boolean.TRUE.equals(value) ? -1 : 0);
+            memory.setInt(offset, (value != null && Boolean.TRUE.equals(value)) ? -1 : 0);
         }
         else if (nativeType == byte.class || nativeType == Byte.class) {
-            memory.setByte(offset, ((Byte)value).byteValue());
+            memory.setByte(offset, value != null ? ((Byte)value).byteValue() : 0);
         }
         else if (nativeType == short.class || nativeType == Short.class) {
-            memory.setShort(offset, ((Short)value).shortValue());
+            memory.setShort(offset, value != null ? ((Short)value).shortValue() : 0);
         }
         else if (nativeType == char.class || nativeType == Character.class) {
-            memory.setChar(offset, ((Character)value).charValue());
+            memory.setChar(offset, value != null ? ((Character)value).charValue() : '\0');
         }
         else if (nativeType == int.class || nativeType == Integer.class) {
-            memory.setInt(offset, ((Integer)value).intValue());
+            memory.setInt(offset, value != null ? ((Integer)value).intValue() : 0);
         }
         else if (nativeType == long.class || nativeType == Long.class) {
-            memory.setLong(offset, ((Long)value).longValue());
+            memory.setLong(offset, value != null ? ((Long)value).longValue() : 0);
         }
         else if (nativeType == float.class || nativeType == Float.class) {
-            memory.setFloat(offset, ((Float)value).floatValue());
+            memory.setFloat(offset, value != null ? ((Float)value).floatValue() : 0.0f);
         }
         else if (nativeType == double.class || nativeType == Double.class) {
-            memory.setDouble(offset, ((Double)value).doubleValue());
+            memory.setDouble(offset, value != null ? ((Double)value).doubleValue() : 0.0);
         }
         else if (nativeType == Pointer.class) {
             memory.setPointer(offset, (Pointer)value);