--- ../../../amber11-orig/AmberTools/src/configure	2010-03-31 22:59:26.000000000 -0400
+++ configure	2010-04-01 16:28:23.000000000 -0400
@@ -1153,14 +1153,21 @@
 if [ "$mpi" = 'yes' ]; then
     sander_rism_mpi='sander.RISM.MPI$(SFX)'
     if [ "$cygwin" = 'no' ]; then
+        rism='yes'
         if [ "$rismmpi" = 'yes' ]; then
+	    if [ -z $XTRA_FLIBS ]; then
+		echo 
+		echo "Error: Compiling 3D-RISM support in MPI NAB requires setting"
+		echo "XTRA_FLIBS to the name of the Fortran MPI libraries for"
+		echo "your MPI distribution.  E.g., for OpenMPI"
+		echo "export XTRA_FLIBS=-lmpi_f77"
+		exit 1
+	    fi
             rismsff="-DRISMSFF"
             nablibrism="librism"
-            rism='yes'
         else
             rismsff=""
             nablibrism=""
-            rism='no'
         fi
     else
         sander_rism_mpi=""