"MUSIC OUT OF PRINT" is the notification we provide when the chart, or sheet music, is no longer available through SAI, thus cannot be ordered via SAI's online store, or through the arranger.
If you already own copyright to the chart, prior to it becoming "out of print", you may still be able to perform it...as long as the original copyright provider has not removed that privilege. It does mean that if you haven't already paid per copy and possibly arranger's fees, you will not be able to order it now.
We may not know the reasons that an arrangement is out of print, but it is best to check with your arranger directly. You can find their web site or email by clicking their name on our Resources/Arrangers list.