Edited some jockey names and not sure exactly the reason for this but seems to be all that comes up when I try to load up a game

I assume you have the weight for each jockey? Count down to jockey 72 or line 72 and look for a mistake. A missing comma or maybe you missed adding a jockeys weight.

Also if you edit jockey/trainer names you must start a new game for it to work. You can't edit data mid game.

Had a little play around and cannot work it out for the life of me. Got a back up may have to have another attempt

The message tells you exactly where the problem is. I think 72 is referring to the 72nd jockey in the list. It might also be line 72.

"Can't get valid jockey lb's" means the weight number is messed up. Maybe a missing comma, extra comma, extra number in the weight

Fixed it now, was looking at line 72 but yeah as you said was jockey 72. Thanks