--- beta.c	2010-03-10 02:57:13.000000000 -0800
+++ beta-proposed.c	2010-07-15 15:12:55.941011520 -0700
@@ -56,7 +56,14 @@
       
       if (x == 0.0 || x == 1.0) 
         {
-          p = exp (gab - ga - gb) * pow (x, a - 1) * pow (1 - x, b - 1);
+	  if (a > 1.0 && b > 1.0)
+	    {
+	      p = 0.0;
+	    }
+	  else
+	    {
+	      p = exp (gab - ga - gb) * pow (x, a - 1) * pow (1 - x, b - 1);
+	    }
         }
       else
         {