I have a go around because i was having the same problem, mine started with seasons but now also happened with bon voyage:
find your icon on your desktop that you use for launching...
next right click and go to properties...find the shortcut tab at the top of the window..
where it says Target ..EAGames\The Sims 2 Bon Voyage\TSBin\ (launcher exe.)...the ending is all you change...where i have the launcher info.
change the launcher to Sims2EP6.exe' From then on when you put in your disk all you do is double click the icon to launch from the cd. It worked for me.