Importing pre-4.0 delay presets via USB stick/Shared folder fails with the message "An unknown error has occurred". This holds even true for pre-4.0 factory delay presets. All OS versions since 4.0 seem to be affected by this bug. Pre-4.0 delays as part of rigs and presets of the effect section cause no problems.
So if you try to import a set of rigs and presets be aware that just one pre-4.0 delay preset in the shared folder will make you sad.
Cheers, René