Mac CS4 install is getting error message with serial number I own

I have Mac CS4 Standard (Photoshop, Illustrator, Indesign, Acrobat, and Dreamweaver (second DVD)). 

I've read all the related topics and none of the solutions work. 

I'm installing CS4 (from a DVD with the (registered with Adobe) serial number on the back of the case) on a new iMac (the old iMac no longer works with internet apps and it won't let me update the system) and when I enter the serial number I get the green "X" for o.k., but then a second later it turns to a red check mark and then shows an error message: "Licensing for this product has stopped working.  Error: 6." 

What does that mean?!! 

I paid a lot of money for this software (more than the cost of the new iMac back then).  I'm not paying again for sofware I already own. 

Imagine buying a car and then 10 years later the car company shuts off your car and says you have to pay more money for the car you already own!!! 

How do I fix this? 

Thanks. 

Richard

p.s. I am currently using it in 30 Day Evaluation mode.