Photoshop launches in Admin account but not in User account??

Question

My 2007 Mac Pro is working fine. Just installed 10.6.7 on freshly wiped HD in Bay #2. Used the migration feature to bring over everything from drive in Bay #1 (which runs 10.5.8). After that: Photoshop CS5 will not launch (on either drive) under the regular user account. Throws 2 messages as follows: "Cannot find scratch disk because disk is unavailable." Then: "Cannot initialize because disk is unavailable."
But - just logged in on my Admin account on the Snow Leopard drive. I then tried (for the first time ever, I think) to launch PS CS5 just to see what would happen. The app launched normally!
This after:
1. using Adobe uninstaller to remove "original" install of PS CS5 from the Snow Leopard drive. Then reinstalling. (first reinstall of THREE). This did not work to make the app launch, still got above messages.
2. Ran permission repairs (I know - you don't have ta tell me.)
3. Ran DiskWarrior - applied new directory to both Leopard and Snow Leopard drives.
4. I then called Adobe support. Let the agent connect to my desktop from where he did another un-install & re-install using downloaded Adobe utility app. (A guy in India ran my Mac Pro in Michigan for 30 minutes while I sat there, entering Admin password when needed for the operations. Amazing.) He also performed Adobe diagnostics. All without success (on the User account).
After that, he gave up and arranged for a higher level agent to call me tomorrow (Wed. 4/13).
5. Adding: during the above Adobe effort, it came to me that I have too many versions of Photoshop. (I had CS, CS3, CS 4 and CS 5.) So - I systematically removed all versions except the original CS from both the Leopard and Snow Leopard drives. I used AppDelete for this removal, hoping to get all pref files, etc. I even deleted an old version of Acrobat - just because I no longer need it. Then I ran DiskWarrior again and used PreferentialTreatment to check for bad prefs: then again installed CS 5 again - on both drives. (Still working in my normal User account.)
6. Adding: all along, I had no trouble launching and using Photoshop Elements 8 on either drive. I had originally set the PSE scratch disk to my RAID storage drives (Bay #3 & #4). So I was sure by then that I had forgotten to apply the same designation for scratch disk of Photoshop CS5. This was the only variable or possibility I knew of at the time. Guessing: I had set CS 5 to use the drive I wiped clean for Snow Leopard and that's why it came up with: "drive not available."
Repeating: it was not until I logged into my Admin account on the Snow Leopard drive and found I could launch Photoshop from that account that I decided to check in here with my question:
Q. What is the remedy for having one account which won't allow launch for some (in this case, just ONE) apps?
Sorry to be long-winded: this was a major, day-long effort and I want to provide a complete picture of what was done to trouble shoot. Thanks in advance for any help.

Answer 1

1. Standard procedure is to do all but a few operations from Standard User accounts: which I have always done. All software installations have been from my original Standard User account.
Actually, most people use their admin accounts for things like installs, and some apps may not be installable from a standard account or may not function properly there, unless they can authenticate to admin privileges to install things in places standard users don't have access.
several complete uninstalls followed by an equal number of reinstalls FROM the original CS 5 install disk made no difference: when in the Standard User account. CS 5 DOES work under the Admin account on the new Snow Leopard installation (on Bootable Drive #2).
That matches with my experiences with Photoshop Elements... it only works if you've got admin privileges, unless you figure out what items are inaccessible from a standard user account and change their permissions.
I'm sure most experienced users would say that sticking with a Regular User account for daily operations is best.
In reality, that's not as prevalent as it probably should be. In part, that may be because of other software that similarly doesn't run on a standard account. In addition, running on an admin account really isn't as much of a risk as it might seem. I finally gave up years ago on using a standard account, and have never had a problem as a result of using an admin account for day-to-day operations. The stuff you can least afford to lose - ie, your documents - you have full access rights to in a standard account anyway, making your data no safer. It's easier to bork the system in an admin account, but the system is easily replaced.
I have seen (here and elsewhere) that creating a new Reg User account is the remedy when something suddenly won't work
That is true, but it's not a magic wand. In this case, though, I don't think that's likely to help. You're welcome to try it, but I highly recommend doing so in a non-destructive way, so that you can easily switch back to your regular account if it doesn't work.