Constant Auto Protect Message on SAPE.Heur.804F3

I am having a problem with my computer, as every time I boot up, I am receiving the following message from Norton: (SAPE.Heur.804F3) detected by Auto-Protect.

I'm assuming the HEUR refers to a heuristic issue?

The thing is that every time I turn it on, the message would appear and the problem would be associated with a different .dll source file each time (ie. ...appdata\local\temp\xxxxxxxx.dll, then on a subsequent time ...appdata\local\temp\aaaaaaaa.dll for example, and each time, the problem is quarantined by Norton Security.  I started experiencing this issue on September 1. The computer that this problem exists on is my laptop that runs on a Windows Vista 64 OS. I use Mozilla Firefox as my web browser. I tried Norton's threat removal tool (I forgot the exact name of the tool). The problem came back when I booted the PC up again. What is causing this and why is it affecting my computer now? What should I do to resolve the issue?