diff --git a/libdjvu/DataPool.cpp b/libdjvu/DataPool.cpp

index 5fcbedf..4c2eaf0 100644

--- a/libdjvu/DataPool.cpp

+++ b/libdjvu/DataPool.cpp

@@ -791,6 +791,8 @@ DataPool::create(const GP<DataPool> & pool, int start, int length)

   DEBUG_MSG("DataPool::DataPool: pool=" << (void *)((DataPool *)pool) << " start=" << start << " length= " << length << "\n");

   DEBUG_MAKE_INDENT(3);

+  if (!pool) G_THROW( ERR_MSG("DataPool.zero_DataPool") );

+

   DataPool *xpool=new DataPool();

   GP<DataPool> retval=xpool;

   xpool->init();