It has been reported that the Wordpress Dashbord in the 3.0+ versions of Wordpress have had trouble upgrading to the latest Wordpress releases. Here is a super easy way to upgrade your wordpress version in one click.
Log into cPanel, click "Softaculous" (under Software/Services towards the bottom)
On the left, expand the "Blogs" menu
Click on "WordPress"
On the top right you will see "Import" - Click that
Enter the directory in which your blog resides. (i.e. if your blog is located in yourdomain.com/blog, just enter "blog" - without the quotes)
Then click "Return to Overview"
At the bottom, you will see the Current Installations.
Next to the version number, you will see a little blue circle shaped arrow. Click that to automatically upgrade your wordpress in one click.
In the future, all you need to do is return to the Overview screen and click that little blue upgrade arrow and that's it.