The Plugin Site

I have CS3. I loaded up the plug ins in my applications/PSCS3/plugins file but they do not show up. I get a message everytime PS loads saying that "one or more plugins are currently not available on your system.
When I check systems info it lists all these plug ins that failed to load and the message states "70s Pop NO VERSION - OS 9 Plug-in not supported.
I am working on OSX 10.5.4.
What am I doing wrong?

The plugin you mention belongs to Harrys Filters which only works under OS9. There will be an OS X version in future, but at the moment you cannot do anything to make it work (other than install OS9 and use Photoshop 7 or earlier).

Thank you so much!
Will any of the Harry Filters work with CS3?

No, because CS3 does not let you run OS9 plugins.