Virex Conflict?
 

I downloaded the upgrade - V1.1 and got an executable file on my desktop. When I double click on it, Virex starts, scans the file and stops. The file will not execute. the Information "tag" on the file says that it is a Scannable File 4 and the "Open with Application" is defaulted to Virex. No other application seems appropriate to set ... I'd really like to run this upgrade. :( Any thoughts from anyone?

Given that you downloaded the 1.1 version from the SereneScreen.com order page <http://www.serenescreen.com/Order/indexmac.asp>, you should have ended up with the file MarineAquaruim_OSXV1-1.sit downloaded to your machine. This file is a compressed StuffIt archive. If your browser (or other tool you used to download the file) did not automatically decompress it, then you need to decompress the archive using StuffIt Expander (which usually is located in /Applications/Utilities in most standard Mac OS X installs). Decompressing the archive will create a folder named "Marine Aquarium". Follow the steps on the order page to install the screen saver into the correct location.

If StuffIt Expander is unable to decompress the archive, then you may have gotten a bad download. Erase it and try downloading it again.