Hello all!
The latest release of Hipster includes a couple of features for modifying pac files:
1) If you open a pac file containing hip files you can replace any sprite by right-clicking and choosing Replace. This will prompt you to select a PNG file (that's the only supported filetype, I think it should suffice). The sprite in the pac file will be overwritten by the selected image.
2) There's a new Explore option on the File menu which lets you examine the contents of any pac file. Again, just right-click on any of the files within the pac and select Replace.
I should mention that I don't actually have a copy of the game and so haven't tested whether or not the updated pac files are accepted or not. If anybody tries it I'd appreciate any feedback.
Firstly, that's not strictly an error message, it's just the program telling you that there are no sprites contained in the pac file (Hipster is predominantly a sprite ripping tool). However once you've extracted the pac files I would expect it to open them successfully, unless they're empty. Have you tried with the latest version? If so, upload the pac file somewhere and I'll look into it.
