If you ever try to debug a script task by setting a breakpoint and the package is on a 64 bit machine it will just ignpore the breakpoint.
I ran into this problem myself a while ago and this week a co-worker also ran into it and asked me how to resolve it.
It is pretty simple, all you have to do is click on Project, then select Debug Properties. Under Configuration Properties, click on Debugging. Make Run64BitRuntime False. See image below.
Now start the debugger again, you will see now that it will stop at the breakpoint.
I also captured it in a video and uploaded it on YouTube, there is even a HD 720p format