Hi,
When I view the source of your page I see the path to the movie specified like this:
Data/Sites/1/flash/MenuDocReg_as2.swf
but it should be
/Data/Sites/1/flash/MenuDocReg_as2.swf
you are missing the / at the beginning so when you visit login at /Secure/Login.aspx it is looking for a Data folder beneath /Secure
Hope it helps,
Joe