If a flash interactivity is transparent and showing the page below and you would like to make it opaque, follow these directions:

Copy the flash file location.
Delete the flash interactivity from the page
Create a new interactivity on the page in the same place and size of type HTML
Paste the following code in for HTML:

<embed width="100%" height="100%" play="true" datalink="//downloads.realviewdigital.com/Advantage Publishing/Brewers Guardian Digital magazine/SPER12-05SpearAd-A4.swf" swliveconnect="true" wmode="opaque" allowscriptaccess="sameDomain" quality="high" name="swf_page26_0" id="swf_page26_0" style="undefined" src="//downloads.realviewdigital.com/Advantage Publishing/Brewers Guardian Digital magazine/SPER12-05SpearAd-A4.swf" type="application/x-shockwave-flash"> 

Change the datalink and src parameters to your flash file location.

The difference is in the wmode is set to opaque rather than transparent.