http://bugs.winehq.org/show_bug.cgi?id=20694
--- Comment #1 from Lawrence E Toal let02do@earthlink.net 2009-11-13 18:25:02 --- Apologies for not including this at first.
To watch the bug in Mozart10, one can open any of the example *.mz scores in ~/.wine/drive_c/Program Files/Mozart10/Samples
Then from the upper toolbar: File | Export | Save page image will open a dialog to select the type of image file in which one wishes to save the score.
Unless there is a score loaded, there are no export options available from the toolbar File | Export |...