Enterprise Images Not Found

We have some broken images after applying the recent patches. Hope you might be able to point us in the right direction. Thanks!

Images working in 4.1-p20150526
Images broken in 4.1-p20150719
Images broken in 4.1-p20150728

Sample path:
/myapp/sc/skins/Enterprise/images/SectionHeader/opener_opened.png

Some web.xml:
<servlet-mapping>
<servlet-name>FileDownload</servlet-name>
<url-pattern>/myapp/sc/skins/*</url-pattern>
</servlet-mapping>

<servlet>
<servlet-name>FileDownload</servlet-name>
<servlet-class>com.isomorphic.servlet.FileDownload</servlet-class>
</servlet>