Why are three newly-downloaded, up-to-date, unrelated applications not starting: "not supported on this type of Mac" *not a PowerPC problem* Today, I downloaded the latest stable versions of three largely unrelated programs: Pixen, Tiled, and Gideros Studio (free Gideros pack).
All three of these programs have crossed out icons, and return the same CoreServicesUIAgent pop-up alert:

"You can't open the application [Pixen/Tiled/Gideros_Studio] because it is not supported on this type of Mac."

I used these three applications, same versions, on a newer, more powerful Mac OS X Lion earlier in the day. My Mac (that has this problem) is running Snow Leopard.

(( I tried downloading Battle for Wesnoth to see if this would happen with all applications, but was unable to run Wesnoth. I believe I got a bad download mirror or something, because the folder didn't seem to decompile correctly and it took a long time to download (this is not important right now, I think. My main problems is these other applications). ))

Earlier in the day I successfully ran StarCraft 2 and a different game launcher. I also used Safari successfully. StarCraft 2 had an update for Macs today that appeared to prevent HotCorners from working at all while SC2 is the active application, whereas they normally worked fine while running SC2 in windowed mode (before today). 
The SC2 mac-specific updates were defined as:


Command-click now properly issues a right-click command to the game.
Enabling the “Disable OS Keyboard shortcuts” option no longer causes a system hang on exit.


I'm not sure if this is important, but it was the only significant thing that happened prior to the topical error. It is only the new downloads that won't run at all, and these were downloaded after the SC2 update that appeared to affect the system (via HotCorners, at least).

I repaired my harddisk permissions, but nothing improved. When I ran the executable from Pixen.app/Contents/MacOS/Pixen, I was returned the following:

Macintosh-3:~ ~$ /Users/~/Downloads/Pixen.app/Contents/MacOS/Pixen ; exit;
-bash: /Users/~/Downloads/Pixen.app/Contents/MacOS/Pixen: Bad CPU type in executable


I got the same error for the other two apps.

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I really have no idea why these three unrelated apps aren't running. Symptoms of a virus? I've never dealt with/experienced virus infections on any of my Mac systems before. Any insight into the causes of this are welcome.

Thank you in advance for your time. I can provide more information if it's needed.
Problem identified. My machine only runs 32-bit at the moment. The latest versions of Tiled are 64-bit, and Gideros is all 64-bit. After a redownload and some minor glitches, Pixen seems to work fine. I downloaded an operational albeit outdated version of Tiled in the mean time. I really need to upgrade to 64-bit.
I guess I overreacted when all three had the same error, and indeed Pixen shouldn't have had the error (and no longer does). I didn't anticipate that Tiled would be 64-bit either. Oh well. Thanks for any and all input.