Messed up permissions

Question

Over the last day I have multiple problems develop that may or may not be related.
I downloaded a plugin (Boris FX) for Adobe Premiere Pro but have had a lot of trouble installing it. Sine then Premiere Pro now constantly crashes citing a generic error "Sorry, a serious error has occurred that requires Adobe Premiere Pro to shut down. We will attempt to save your current project" I have been searching Adobe forums for solutions. Some of them involved deleting Adobe preferences and Im worried I have deleted something important.
My iMac permissions are now messed up - everytime I want to delete anything (documents, photos) I now have to type in my password. I tried to repair permissions but to no avail.
At the same time as all this, Firefox crashed and now everytime I restart it tries to restore the previous session. I have deleted Firefox and reinstalled it but the same thing happens.
The only way to get Premiere Pro to work is by creating a new user on my Mac.
Should I do a complete wipe of my iMac back to factory settings to fix these problems?
Thanks.
iMac 27-inch, Mid 2011
Processor  3.4 GHz Intel Core i7
Memory  4 GB 1333 MHz DDR3
Graphics  AMD Radeon HD 6970M 2048 MB
Software  Mac OS X Lion 10.7.3 (11D50b)
  Model Name:
iMac
  Model Identifier:
iMac12,2
  Processor Name:
Intel Core i7
  Processor Speed:
3.4 GHz
  Number of Processors:
1
  Total Number of Cores:
4
  L2 Cache (per Core):
256 KB
  L3 Cache:
8 MB
  Memory:
4 GB
  Boot ROM Version:
IM121.0047.B1F
  SMC Version (system):
1.72f2
  Serial Number (system):
C02G60EZDHJW
  Hardware UUID:
5925F667-8343-5917-8B32-4939121C9BCA

Answer 1

Repairing the permissions of a home folder in Lion is a complicated procedure. I don’t know of a simpler one that always works.
Back up all data now. Before proceeding, you must be sure you can restore your system to its present state
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the page that opens.
Drag or copy — do not type — the following line into the Terminal window, then press return:
chmod -R -N ~
The command will take a noticeable amount of time to run. When a new line ending in a dollar sign ($) appears below what you entered, it’s done. You may see a few error messages about an “invalid argument” while the command is running. You can ignore those. If you get an error message with the words “Permission denied,” enter this:
sudo !!
You'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up.
Next, boot from your recovery partition by holding down the key combination command-R at startup. Release the keys when you see a gray screen with a spinning dial.
When the recovery desktop appears, select Utilities ▹ Terminal from the menu bar.
In the Terminal window, enter “resetpassword” (without the quotes) and press return. A Reset Password window opens. You’re not going to reset the password.
Select your boot volume if not already selected.
Select your username from the menu labeled Select the user account if not already selected.
Under Reset Home Directory Permissions and ACLs, click the Reset button.
Select  ▹ Restart from the menu bar.