Try this:
1. Open the Waterloo Tool
2. At the bottom where it says Version make sure you select your correct version from the dropdown menu ie PES4, WE8 etc. In your case PES4.
3. At the bottom where it says "File Name", click the small unmarked square button to the right of the long white section.
4. Find your param_dat.bin_000 file you made with the zlib_tool and click open.
5. Click the big "Retrieve File Button located to the bottom right of the Waterloo Tool
6. Now you can edit your param_dat.bin_000. When you are happy press "Write File" button and your changes will be saved in your param_dat.bin_000 file
7. Now open your zlib_tool and drag your updated param_dat.bin_000 through it. This will uodate your original param_dat.bin. Delete your param_dat.bin_000 so you don’t get confused.
8. Then import the file back into your AFS.
Any probs, let me know.