A known bug for Flash prevents HTML elements from appearing on top of Flash content. This is most noticeable if you have a Flash video in the sidebar of your site, and the Qualaroo survey appears on the same side.
One solution is to add the wmode=opaque parameter to the <embed> tag for your Flash content. This is explained in more detail in this blog post.
Alternatively, if your Flash content is located on the right side of the page, you have the option of moving the survey to another area of the screen. This option is available in the "Design" area of your survey.