Yes it is a security issue. You are running some ActiveX (msorun.dll) on your site to make the text slide and fade. This is one of the greatest security risks in IE. ActiveX is very powerful and can easily be abused. Under default settings IE7 blocks any ActiveX that has not been explicitly allowed by the end user.

I suggest you find another way to make your graphic. like a .gif or flash program.
Here are a couple of options for you.
GIMP - The GNU Image Manipulation Program (great graphics program too)
GIMP - Tutorials

Toufee - Create Flash Movies with the #1 Flash Movie Maker!