There are quite a few people here that had this problem, but the solutions I found aren't working.
Here is the iframe embed code that I got from Google Maps:
<iframe width="640" height="480" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://maps.google.com/maps/ms?msa=0&msid=216410867472561730082.0004d44aa7eec841d333d&ie=UTF8&t=h&ll=40.696778,-73.978543&spn=0.015618,0.027466&z=15&output=embed"></iframe><br /><small>View <a href="https://maps.google.com/maps/ms?msa=0&msid=216410867472561730082.0004d44aa7eec841d333d&ie=UTF8&t=h&ll=40.696778,-73.978543&spn=0.015618,0.027466&z=15&source=embed" style="color:#0000FF;text-align:left">Taskeyo Example 2</a> in a larger map</small>
The console says
Refused to display document because display forbidden by X-Frame-Options.
followed by a lot of unsafe JS errors.
The embed code already has &output=embed in it, which seems to be the fix that I need.
Anyone else ever get this error? I only wrapped the iframe in a div (inside a jQuery UI accordion) and it used to work! I appreciate the help.