I know you are frustrated from updating and that is understandable. BUT: we should be able to fix it for you. BTW: this forum is NOT Apple Support: we are just Apple users like you who share our knowledge and help.
What model iMac did you recently update? Under the Apple Menu, go to About this Mac and tell us what it says; and then click MORE INFO and SYSTEM REPORT and tell us what Model Name and Model Identifier.
Your older Mac is the iMac G4 "Luxo" (so called, because it looks like the Luxo logo of Pixar turned upside down, the character from Pixar's first short film). Chances are you were using Tiger OS X 10.4.x; maybe upgraded to Leopard OS X 10.5.x. It does not support Snow Leopard or above.
My daughter purchased that iMac and we still have it and it works with Leopard OS X 10.5.8. I do not remember it coming with Quicken 2006, as I would have commandered it for my collection because I was using Quicken Deluxe 2002 up until Intuit released Quicken 2007 for Lion. But if you say that is where you got it, you must be correct.
Can you restore your newer iMac back to whatever version of OS X that it was running before? Do you have a Time Machine backup? Or other suggestions to restore the older OS X are here:
https://discussions.apple.com/thread/4454055?answerId=20095881022#20095881022
Downloading the new Quicken 2007 for Lion before you upgraded is usually not an issue. There is a data upgrade issue BEFORE you upgrade if you, like me, were using a version of Quicken older than 2005. Then you must use Quicken 2006 or Quicken 2007 PPC version on a Mac that will run it (i.e., pre-Lion or Mountain Lion) to update the older data file to one that will work in Quicken 2007 for Lion.
When you say something about a "qif" file; where are you hearing this and in what context? This should not come up in this context, but maybe if you were using Quicken on a PC. Were you using Quicken 2006 on a PC and not a Mac before?
Quicken 2006 CD means you are using exactly that and not Essentials: GOOD!
Does your iMac Luxo have Quicken 2006 installed on it? If not, what version is installed on it? If not, perhaps you can use your Quicken 2006 CD to install Quicken 2006 and again attempt to access your old Quicken data file and see if this works.
Lastly, if you feel comfortable with emailing me your old data file, I can do the translation work for you and resend it back to you to use with Quicken 2007 in Lion. I can understand if you feel that this is sensitive data and do not want to share it with a stranger...