Don't make your VLCPlayer class implement ActionListener; instead add a suitable ActionListener to each of your buttons. The commented-out code starting at line 87 contains the code which should be the body of each of those two ActionListeners. (Although you might have to reorder the code in the constructor so that the code in the ActionListeners knows about the mediaPlayer variable.)
Please post more than abbreviated sentences; it's hard to understand what problem you are facing. "normally the progress time bar which is increasing when video plays" gives us just about nothing to work with: TellTheDetails
Seeing relevant code excerpts (NOT the entire GUI code) would also help, as we don't know the code you are currently working with.