TTL flash on E-TTL DSLR?

[Canon Fan]

Decided to start a new topic for my new problem. Forum member usayit did try to warn me about this but I'm still unsure if this is a problem with the flash or my camera. The other topic can be found here . . .

http://www.thephotoforum.com/forum/viewtopic.php?p=101663#101663

Here is what I have now . . .

Canon 10D DSLR body
Quantaray PZ-1 DSZ TTL Flash
Quantaray QTB 7500-A TTL Flash

My problem/question is why will the cheaper QTB 7500-A TTL Flash fire on the 10D but the more advanced PZ-1 will not? Everything will work just fine except the distance scale and it will not fire in any mode at all. It was my understanding that this flash would still work in TTL mode or at the very least in manual mode. Is there a problem with my camera or am I stuck with an E-TTL only flash such as the Canon 550EX?

The PZ-1 does however perform flawlessly on my Canon Rebel 2000 film SLR body.

 

[Canon Fan]

Also I noticed that there is a "ELAN7e PASSED" sticker on the flash head. I see that the Elan 7E used A-TTL flash metering? Is A-TTL that much different than E-TTL?

I just think Canon wants even more of my money after they got me to spend a truckload on a new DSLR. Don't they have enough already!!!