What did you do once you did this? In the version of RetroPie I configured it came already installed, and ES sees the .d64 and .t64 files I dropped into the appropriate folder, but when I launch one it just goes to the standard C64 boot screen and I can’t get the image to launch, not even with a “LOAD “*”,8,1″. The configured command is the same as yours but with the %ROM% environment variable tacked onto the end, as in:
/opt/retropie/emulators/vice-2.4/installdir/bin/x64 -sdlbitdepth 16 %ROM%