The caps.db file should be at C:\Program Files (x86)\Common Files\Adobe\caps on a 64 bit system...
Was this an upgrade from a previous version of Creative Suite, or a full version? Are tehre any other Adobe products present on the system?
The CS3 installers were probably the worst in Adobe history. A lot of things would conflict with a good install. My first attempt way back when failed because the DVD drive wouldn't read the disk properly. You can try copying the disk to the desktop and install from there.
I've got CS3 running on two different win 7 64-bit machines (but I only installed ID from the suite, though I don't think that should be an issue), so it should be possible. I'd start by cleaning up anything left over from your failed attempts. If you have other versions later than CS3, that probably means uninstalling them, too, then uninstall CS3 if it appears in the list in Windows' Control Panel, then download and run the clean tool from Adobe: CS Cleaner Tool for installation problems | CCM, CS6, CS5.5, CS5, CS4, CS3
After running the tool reboot. Flash Player was also a major cause of failed installs on CS3, so you may need to also see http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html, then reboot again. Run MSconfig from the Run command in the start menu. The object here is to turn off everythign that is not essential to running the system, without actually going into Safe Mode. On the Startup tab you should be able to uncheck pretty much everything (if you see a mouse driver, I'd leave that), but you want to be sure to especially turn off anti-virus, anti-malware, third-party firewall, iTunes, and any browser helpers and toolbars you see. In the services tab, check the box to hide Microsoft Services, then look for anything that looks like it might be from your anti-virus or malware scanners and uncheck those. Leave anything that says Flexnet or ##ID_String... active, if you see them (you may not), then close MSconfig and reboot when prompted.
When you restart you'll see a warning about running in diagnostic mode, or some such, and yo may be asked if you want to run MSconfig again. You want to continue in diagnostic mode. If MSconfig opens, press the cancel button. Run the installer again. Hopefully this time it will work and youcan the reboot one more time, run MSconfig and check the Normal Startup box, let the system restart again, and you should be good to go.