You said in the original post:
I tried to go onto the Location of Zipfile and tried unzipping it manually and it all works good.
Was that just double-clicking on the file to open it interactively in Winzip or did you do that from the command line, using the same command line the Execute Process Task would issue? I am just trying to establish that it is working from the command line as a baseline so we know to focus on the Execute Process Task.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato