Index: boost/random/lagged_fibonacci.hpp
===================================================================
--- boost/random/lagged_fibonacci.hpp	(revision 50996)
+++ boost/random/lagged_fibonacci.hpp	(working copy)
@@ -317,12 +317,14 @@
     unsigned long mask = ~((~0u) << (w%32));   // now lowest w bits set
     RealType two32 = pow(RealType(2), 32);
     unsigned int j;
-    for(j = 0; j < long_lag && first != last; ++j, ++first) {
+    for(j = 0; j < long_lag && first != last; ++j) {
       x[j] = RealType(0);
       for(int k = 0; k < w/32 && first != last; ++k, ++first)
         x[j] += *first / pow(two32,k+1);
-      if(first != last && mask != 0)
+      if(first != last && mask != 0) {
         x[j] += fmod((*first & mask) / _modulus, RealType(1));
+        ++first;
+      }
     }
     i = long_lag;
     if(first == last && j < long_lag)
Index: libs/random/random_test.cpp
===================================================================
--- libs/random/random_test.cpp	(revision 50996)
+++ libs/random/random_test.cpp	(working copy)
@@ -238,17 +238,17 @@
   std::vector<int>::const_iterator it_end = v.end();
   URNG urng3(it, it_end);
   BOOST_CHECK(it != v.begin());
-  std::cout << "; seeding uses " << (it - v.begin()) << " words" << std::endl;
+  std::vector<int>::const_iterator::difference_type n_words = (it - v.begin());
+  std::cout << "; seeding uses " << n_words << " words" << std::endl;
 
-  bool have_exception = false;
-  try {
-    // now check that exceptions are thrown
+  it = v.end();
+  BOOST_CHECK_THROW(urng3.seed(it, it_end), std::invalid_argument);
+
+  if(n_words > 1) {
     it = v.end();
-    urng3.seed(it, it_end);
-  } catch(std::invalid_argument& x) {
-    have_exception = true;
+    --it;
+    BOOST_CHECK_THROW(urng3.seed(it, it_end), std::invalid_argument);
   }
-  BOOST_CHECK(have_exception);
 
   // check for min/max members
   ResultType min = (urng3.min)();