diff --git a/SMILEBASIC/VM.d b/SMILEBASIC/VM.d
index 5db310b..cd89a4f 100644
--- a/SMILEBASIC/VM.d
+++ b/SMILEBASIC/VM.d
@@ -1138,6 +1138,7 @@ class PushArray : Code
                 index[i] = cast(int)v.doubleValue;
                 continue;
             }
+            vm.dumpStack(vm.stacki + 1);
             throw new TypeMismatch();
         }
         Value array;
diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index a1870f5..06ea1b0 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -1437,7 +1437,7 @@ class BuiltinFunction
     {
         p.sprite.spshow(id);
     }
-    static void SPOFS(PetitComputer p, int id, DefaultValue!double x, DefaultValue!double y, DefaultValue!(double, false) z)
+    static void SPOFS(PetitComputer p, int id, DefaultValue!double x, DefaultValue!double y, double z)
     {
         if (x.isDefault || y.isDefault)
         {
@@ -1446,14 +1446,18 @@ class BuiltinFunction
             x.setDefaultValue(x_);
             y.setDefaultValue(y_);
         }
-        if(z.isDefault)
+        p.sprite.spofs(id, cast(double)x, cast(double)y, z);
+    }
+    static void SPOFS(PetitComputer p, int id, DefaultValue!double x, DefaultValue!double y)
+    {
+        if (x.isDefault || y.isDefault)
         {
-            p.sprite.spofs(id, cast(double)x, cast(double)y);
-        }
-        else
-        {
-            p.sprite.spofs(id, cast(double)x, cast(double)y, cast(double)z);
+            double x_, y_, z_;
+            p.sprite.getspofs(id, x_, y_, z_);
+            x.setDefaultValue(x_);
+            y.setDefaultValue(y_);
         }
+        p.sprite.spofs(id, cast(double)x, cast(double)y);
     }
     @StartOptional("z")
     static void SPOFS(PetitComputer p, int id, out double x, out double y, out double z)
diff --git a/SMILEBASIC/compiler.d b/SMILEBASIC/compiler.d
index e7f4bff..55a372e 100644
--- a/SMILEBASIC/compiler.d
+++ b/SMILEBASIC/compiler.d
@@ -486,7 +486,7 @@ class Compiler
     }
     void compileExpression(Expression exp, Scope sc)
     {
-        if(!exp)
+        if(!exp || exp.type == NodeType.VoidExpression)
         {
             genCodeImm(Value(ValueType.Void));
             return;