I believe you are just trying to load the .ips file alone.
If you haven't already, patch the rom! Here's how-
1. download floating IPS here
2. if you haven't already, use google to search for a "super mario world rom".
3. put the hack, the rom, floating IPS and zsnes all into one folder. This isn't necessary, but makes things easier.
4. Download ROMclean Here
5. Rename your Super mario world rom to "Super Mario World." Again, this makes things a lot easier.
6. Go to properties of the rom, and see if it is a .smc or a .sfc file. Remember this
7. Open rom clean, then type in either
"Super Mario World.smc"
"Super Mario World.sfc"
make sure the .s blah blah is the same .s blah blah you saw in properties. Try both, it won't hurt.
8. once your rom is clean, open floating IPS.
9. Click on "Apply IPS patch"
10. Find your rom hack when it opens up file explorer the first time"
that will close when you click on the hack, then open up again
this time, click on your rom
once more, file explorer will close and reopen itself. This time you will be making a destination for the playable ROMHACK you put togehter. Name it whatever you like, then hit save.
11.go to ZSNES (or ZMZ, I use both of them) and find the rom you applied the patch to.