problem with libSage++.a

When trying to compile a simple test program as follows

#include "/home/R8G/lxm/sage++-1.7/lib/include/sage++user.h"
  SgProject P("myp.proj");
  for(int i=0; i<P.numberOfFiles();i++) {
   printf("file is %s\n", P.fileName(i));

with the command line:
 g++ try.C -L/home/R8G/lxm/sage++-1.7/lib/alpha -lSage++

I got the following message:
ld: /home/R8G/lxm/sage++-1.7/lib/alpha/libSage++.a(________64ELEL_): bad magic 
collect: /usr/bin/ld returned 4 exit status

Do you have any idea what's going on ? Thanks !