--- tree.cpp	2010-08-06 15:50:05.883899976 -0700
+++ tree.cpp	2010-08-06 15:50:55.623914910 -0700
@@ -228,15 +228,19 @@
     if( _sample_idx )
     {
         CV_CALL( sample_indices = cvPreprocessIndexArray( _sample_idx, sample_all ));
-        sidx = sample_indices->data.i;
-        sample_count = sample_indices->rows + sample_indices->cols - 1;
+        if ( sample_indices ) {
+            sidx = sample_indices->data.i;
+            sample_count = sample_indices->rows + sample_indices->cols - 1;
+        }
     }
 
     if( _var_idx )
     {
         CV_CALL( var_idx = cvPreprocessIndexArray( _var_idx, var_all ));
-        vidx = var_idx->data.i;
-        var_count = var_idx->rows + var_idx->cols - 1;
+        if ( var_idx ) {
+            vidx = var_idx->data.i;
+            var_count = var_idx->rows + var_idx->cols - 1;
+        }
     }
 
     is_buf_16u = false;     
@@ -863,20 +867,22 @@
     if( _subsample_idx )
     {
         CV_CALL( subsample_idx = cvPreprocessIndexArray( _subsample_idx, sample_count ));
-        sidx = subsample_idx->data.i;
-        CV_CALL( subsample_co = cvCreateMat( 1, sample_count*2, CV_32SC1 ));
-        co = subsample_co->data.i;
-        cvZero( subsample_co );
-        count = subsample_idx->cols + subsample_idx->rows - 1;
-        for( i = 0; i < count; i++ )
-            co[sidx[i]*2]++;
-        for( i = 0; i < total; i++ )
-        {
-            int count_i = co[i*2];
-            if( count_i )
+        if ( subsample_idx ) {
+            sidx = subsample_idx->data.i;
+            CV_CALL( subsample_co = cvCreateMat( 1, sample_count*2, CV_32SC1 ));
+            co = subsample_co->data.i;
+            cvZero( subsample_co );
+            count = subsample_idx->cols + subsample_idx->rows - 1;
+            for( i = 0; i < count; i++ )
+                co[sidx[i]*2]++;
+            for( i = 0; i < total; i++ )
             {
-                co[i*2+1] = cur_ofs*var_count;
-                cur_ofs += count_i;
+                int count_i = co[i*2];
+                if( count_i )
+                {
+                    co[i*2+1] = cur_ofs*var_count;
+                    cur_ofs += count_i;
+                }
             }
         }
     }