If not running Lion, please do this:
With the Finder active, press the following key combinations, in this order:
Shift-Command-H
Command-3
Command-I
The Info window for your home folder will open. Click the lock icon to authenticate. In the Sharing & Permissions section, you should have read & write access. If not, make it so. Regardless of whether you made any changes, select "Apply to enclosed items" from the action (gear icon) menu.
If running Lion, do this:
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.
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 Apple menu > Restart from the menu bar.