The lik in that post is down so i uploaded mine:
After downloading, unpack the .zip and follow the same instructions as in that post.
The Update also includes Infrastructure Online Multiplayer
I'll inform the devs about this issue, see if they can get it working.
1. Make sure you copied the UCUS98646 folder into PSP/GAME and not just the files inside the folder
2. Make sure the .zip file you downloaded is exactly 73.42MB
3. Make sure you have a US copy of the game. If you live in Europe and have the PAL version there are probably compatibility issues (try changing the name of the folder to UCES00279 but i can't guarantee it works as i've never tried it myself)
If you've tried all that and it still doesn't work, let me know and i'll re-upload the files. Maybe something went wrong in the upload.
I tried the very same file yesterday and it worked just fine.