Yup...Adobe has announced that future versions (starting with CS5) of Premiere Pro and AE will support only 64 bit systems on both Mac and Windows.
Adobe's site has a FAQ here:
http://www.adobe.com/products/creativesuite/production/faq/
go down to "Support for 64 bit operating systems"...
It was inevitable...having enough RAM has been a constant issue with both AE and PPro for years, and cutting loose 32 bit legacy support will hopefully result in a stable platform.
Now if I could just get all the drivers for all the other components in my workstation to run properly under 64 bit, I'll be a happy editor.
...and now my venerable Dell M90 will be frozen in time...ah well...onward.
TimK,
Director, Consultant
Kolb Productions,