diff --git a/sit b/sit
index 954269a..2f6e92e 100755
--- a/sit
+++ b/sit
@@ -70,7 +70,8 @@ export ${COMPILER_OPTS}
 if [ ! -z "$MPI" ] ; then 
     MPI_MODULE="mpi/$MPI"
     if [ ! -z "$MPI_VERSION" ] ; then
-        MPI_MODULE=${MPI_MODULE}${MPI_VERSION:+"/${MPI_VERSION%%-*}-$COMPILER-$COMPILER_VERSION"}
+        MPI_VERSION_NUM=${MPI_VERSION%%-*}
+        MPI_MODULE=${MPI_MODULE}${MPI_VERSION_NUM:+"/${MPI_VERSION_NUM}-$COMPILER-$COMPILER_VERSION"}
     fi  
     echo "Loading MPI module ${MPI_MODULE}"
     module load $MPI_MODULE
@@ -90,7 +91,7 @@ fi
 
 # construct the final installation directory path
 PREFIX="${PREFIX_BASE}/${CATEGORY}/${PACKAGE}/${VERSION}"
-PREFIX_SUFFIX=${MPI:+"-$MPI"}${MPI_VERSION:+"-$MPI_VERSION"}
+PREFIX_SUFFIX=${MPI:+"-$MPI"}${MPI_VERSION_NUM:+"-$MPI_VERSION_NUM"}
 PREFIX_SUFFIX=$PREFIX_SUFFIX${COMPILER:+"-$COMPILER"}${COMPILER_VERSION:+"-$COMPILER_VERSION"}
 PREFIX_SUFFIX=$PREFIX_SUFFIX${PACKAGE_DESCRIPTOR}