diff --git a/trunk/paradiseo-peo/src/rmc/mpi/mess.cpp b/trunk/paradiseo-peo/src/rmc/mpi/mess.cpp
index c65fc49e8..c45f94a6e 100644
--- a/trunk/paradiseo-peo/src/rmc/mpi/mess.cpp
+++ b/trunk/paradiseo-peo/src/rmc/mpi/mess.cpp
@@ -338,6 +338,7 @@ void unpack (std::string & __str)
   char * buffer;
   int len;
   MPI_Unpack (mpi_buf, MPI_BUF_SIZE, & pos_buf, & len, 1, MPI_INT, MPI_COMM_WORLD);
+  buffer = new char[len+1];
   MPI_Unpack (mpi_buf, MPI_BUF_SIZE, & pos_buf, buffer, len, MPI_CHAR, MPI_COMM_WORLD);
   __str.assign( buffer );