http://bugs.winehq.org/show_bug.cgi?id=18345
--- Comment #25 from Rosanne DiMesio dimesio@earthlink.net 2012-02-03 21:26:23 CST --- In 1.4-rc2, the Silverlight 4 installer that I tested previously still fails, and the workaround in comment 23 does not work.
The installer currently available for download is for Silverlight 5. That does install, though the automatic update at the end fails.