Si tu as installé la dernière version, elle ne supporte plus les "vieux" boitiers :
Technical support is no longer available for the following models when used with this version of EOS Utility:
EOS D30, EOS D60, EOS 10D, EOS 20D, EOS 20Da, EOS 5D, EOS 300D DIGITAL, EOS 350D DIGITAL, EOS-1D, EOS-1D Mark II, EOS-1D Mark II N, EOS-1Ds, EOS-1Ds Mark II (it is recommended to use EOS Utility 2.7 with these models)
Il faut donc utiliser la version 2.7 et c'est un problème si t'as un boitier récent et un "vieux"...