I'm going to guess that this was never solved.
I am using Quicken 2007 for Lion on a iMac running Lion. I have my Quicken data file inside my shared "Public" folder because my wife and I access it from different computers in the house using our household network. This lets us have one Quicken file for about 50 accounts we have, everything from checking to credit cards to brokerage accounts.
So here is what I did to solve the problem I had when I received the error message, "Quicken has found corrupt data in your file. If you continue to use this file you may experience program instability, further date corruption, and incorrect results."
First, I have learned from decades of experience with Quicken for Mac that when you get an error message it almost never tells you what the real problem is. Quicken has a way of just popping up bogus messages and you need to figure out what is really wrong. Something is wrong, just not what it tells you is wrong.
I selected the default, which said something to the effect that I could go to the Quicken help page to solve my problem. The other choices were, "Continue," and "Quit." The Quicken help page told me to delete the "Quotes" file located in the Package Contents of my data file. i did what I was told, but that did not solve the problem. I realize now that true to form, the error message was not even close to wha the real problem was.
Then I went back and tried the "Continue" button. I got the error message that the file was locked (if I remember correctly). My next step was to use Time Machine to simply restore a backup. I LOVE TIME MACHINE. It has saved me from all kinds of problems. The problem I got with Time Machine was that it would try to restore my file, but would give me a message that I didn't have permission. This is garbage. I'm working on my own Mac, my own files, I'm the only user on the machine, how dare it tell me I don't have permission. This is another case of getting the wrong error message for the problem at hand.
So I called Quicken. They dold me that the problem was indeed solvable, but that I needed to buy a support package. I said I'd think about it and hung up.
Then I went back into Time Machine and instead of trying to restore only the Quicken data file, I restored the entire folder that the Quicken data file was in. That did it. No permission errors. Quicken opened just fine, albeit with a days worth of entries missing.
I hope this saves somebody from a day of heartache and solves their problems fast.
Good luck.