In 0.7.3, the layout of the Drivers section was changed. In both the Sample.plist and CustomSample.plist files, the first driver in the Drivers section is listed as HfsPlus.efi. This should be OpenHfsPlus.efi. If you copy this section verbatim to your config.plist, OC will stop with a critical error saying "HfxPlus.efi at 0 cannot be found".
In 0.7.3, the layout of the Drivers section was changed. In both the Sample.plist and CustomSample.plist files, the first driver in the Drivers section is listed as HfsPlus.efi. This should be OpenHfsPlus.efi. If you copy this section verbatim to your config.plist, OC will stop with a critical error saying "HfxPlus.efi at 0 cannot be found".