What's happening to my Photoshop C3 on the imac? [CS3 is DEAD]

Creative Suite 3 is discontinued, unsupported software.  The activtaion servers are long gone.  And unless you have an older OS to support it, CS3 is dead to you.

MODERN OPTIONS:
Photoshop Elements (approx $100, no subscription needed)
https://www.adobe.com/products/photoshop-elements.html

Creative Cloud Photography Plan -- approx $10/month x 12 months. Includes the very latest versions of these great products & services:
-- Photoshop CC and Photoshop on iPad
-- Lightroom on desktop, mobile and the web
-- Lightroom Classic
-- Portfolio website + hosting
-- Spark with premium features
-- Bridge
-- 20 GB cloud storage (upgradable to 1 TB).
https://www.adobe.com/creativecloud/photography.html

Creative Cloud All Apps (31 + apps & services) and Single Apps Plans
https://www.adobe.com/creativecloud/plans.html

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Beware of fake Adobe reps who may contact you privately offering to sell you software or take control of your computer. It's a scam, run away!
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3 Easy Ways to Identify Genuine Adobe Staff
https://tinyurl.com/10791730

Let me move this to the Creative Cloud Services forum for you, where I hope you will find an answer for your question.

The Using the Community forum is for help in using the Adobe Support Community forums, not for help with specific programs. Product questions should be posted in the associated product community.

As an aside, most people here would prefer that you insert your screenshots or pictures within the body of your post to avoid security issues concerning downloading files from unknown sources. I believe it is now possible to do this in replies, so if you could respond with the graphic inline, that would be appreciated.

Without looking at your graphic, though, I can tell you that CS3 will not run on any Mac OS from Catalina onward. If you are trying to install it on a new machine you are out of luck entirely, as it is no longer possible to activate the program. The activation servers were turned off for CS1 through CS3 over a year ago.