diff --git a/dsf/org.eclipse.cdt.examples.dsf.pda/pdavm/src/org/eclipse/cdt/examples/pdavm/PDAVirtualMachine.java b/dsf/org.eclipse.cdt.examples.dsf.pda/pdavm/src/org/eclipse/cdt/examples/pdavm/PDAVirtualMachine.java
index b3051199b45..9735d7f7991 100644
--- a/dsf/org.eclipse.cdt.examples.dsf.pda/pdavm/src/org/eclipse/cdt/examples/pdavm/PDAVirtualMachine.java
+++ b/dsf/org.eclipse.cdt.examples.dsf.pda/pdavm/src/org/eclipse/cdt/examples/pdavm/PDAVirtualMachine.java
@@ -662,6 +662,9 @@ public class PDAVirtualMachine {
             try {
                 if (allThreadsSuspended || fCommandReceiveStream.ready()) {
                     line = fCommandReceiveStream.readLine();
+                    if (line == null)
+                    	return;
+                    
                     processDebugCommand(line);
                 }
             } catch (IOException e) {
@@ -698,6 +701,10 @@ public class PDAVirtualMachine {
                 System.exit(1);
                 return;
             }
+            
+            if (line == null)
+            	break;
+            
             processDebugCommand(line);
         }
 
diff --git a/dsf/org.eclipse.cdt.examples.dsf.pda/src/org/eclipse/cdt/examples/dsf/pda/service/PDAExpressions.java b/dsf/org.eclipse.cdt.examples.dsf.pda/src/org/eclipse/cdt/examples/dsf/pda/service/PDAExpressions.java
index 9d0f563a697..378d50a4ce1 100644
--- a/dsf/org.eclipse.cdt.examples.dsf.pda/src/org/eclipse/cdt/examples/dsf/pda/service/PDAExpressions.java
+++ b/dsf/org.eclipse.cdt.examples.dsf.pda/src/org/eclipse/cdt/examples/dsf/pda/service/PDAExpressions.java
@@ -139,6 +139,9 @@ public class PDAExpressions extends AbstractDsfService implements ICachingServic
     
         @Override
         public boolean equals(Object other) {
+        	if (other == null)
+        		return false;
+        	
             return super.baseEquals(other) && 
                 fExpression == null 
                     ? ((InvalidExpressionDMContext) other).getExpression() == null