Okay, well I got this the day of the release of the beta 15. I added Roc's Feather among things and my quest file stopped working in ZC. It would freeze ZC when trying to open it, however, I could still work on work on the file on Zquest. I was trying to figure out what happened to my quest file to make it not work on ZC. And I found out it was the custom subscreen. I know for sure because I switched it back to Revision 2 and the game worked on ZC again. I only thing I can remember doing to make it mess up, was switching it to custom subscreen and then putting Roc's Feather in and messing with the arrows on the right side because it wasn't locking on the Roc's Feather.
So basically I don't know what I did. I know I didn't add anything except for that item. But yeah, I waited a couple of days to see if I could figure it out, but I couldn't, but thought I may as well let you know about it.