Whatever you do, DON'T go into the 8th gym. There is a glitch where when you check your bag or Pokémon, you are somebody else! And you can't even move around or battle. Does anyone know how to fix it?

gamedude : Have you actually played all the way through the game? Also, the game is a beta, in which betas have a lot of bugs and some betas can't be completed due to program problems in a beta.

Actually, you have a point there. Most hacks, if not all that are made are not complete. If it looks done most likely there are glitches that prevent you from completing it.  I recently realized this when I found out I couldn't complete Pokémon Light Platinum due to a glitch or bug that prevented me from going any further.

However, I believe he just wanted to know how to get past the glitch in the 8th city. And I don;To know why it happens but, I do know how come.
It happens when:

A:You hit the start and enter the menu or,
B:You exit the gym before beating all the trainers.

Now seeing as you can't avoid the black belt's line of sight he ends up blocking you which means that in order to progress to the next trainer,
naturally the solution here would be to exit the gym and re enter so the path to the gym leader isn't blocked. However as I stated before, once you exit the gym, then after beating the next trainer you get glitched thus prevent you from beating the game. So as it seems there is no way around it.

 Now I would love to figure out if there is a method of getting past the 8th gym, but as it stands, doing so is utterly impossible at the moment.

Yeah it's just a beta - I found this game by a fluke on Youtube and added it to the RGR - the author is probably not going to update it, at least not that I know of, but it could happen.

gamedude : Yeah I got so mad when I came to this fluke. I spent days playing this game. I got my team to the 80's and was ready to face the leader, BOOM! glitch and I spent an hour trying to get around it but I couldn't. Even though I despised not getting around it, I did enjoy the game.