What exact version number of AE are you using (down to the last decimal)?
What are your computer's specs?
What format and codec is that footage?
Are there any effects applied to that footage layer?
How many layers are in your comp? (What are they?)
You simply duplicate the layer with the clone stamp work and that happens?
Can we see a screenshot of your gui interface before and after the duplication?
Well I got it worked out. Apparently I needed to recompense the layer I painted before I duplicated it. Once I did that, I did a freeze frame, masked around it and it worked fine!
Glad you got it sorted.