michael, the reason should be foun basically in what it says: the device is busy.
especially laptops mostly have just a built-in soundcard (without ASIO drivers) and no midi device at all.
you possibly have some midi USB device attached or are using Midi-over-Lan or similar - set this device to be used in *options* of the Vienna Instruments player.
for the audio device in most cases windows grabs the device for itself (media player, ect) and does not allow multiple access - try playing around with your audio settings (properties of audio hardware ... something related to *exclusive use* or similar wording depending on your drivers) or install the Asio4all driver.
this does not apply if you have a seperate audio device - then select this device also in options of the VI player
christian
and remember: only a CRAY can run an endless loop in just three seconds.