EVACUATED object entered! (when doing FFI)

Good morning, I wrote a very small program, and it executed ok. I wanted to export a function in "C", and therefore wrote a "C" wrapper function over it to invoke peekCString and peekArray on the input; newCString and newArray on the output. I then did a small "C" driver program. Everything compiled and linked correctly. But at execution the program prints : EVACUATED object entered! as soon as "startupHaskell" is invoked (i.e. even before I call my foreign exported function !) What is the meaning of this message ? Thank you Francis Girard Le Conquet France