Unfortunately, the issue still persists. "Couldn't find file 'gui/textbox.png'" is still there on default resolution, and the fullscreen option displays the textbox, but it is offset.
Thank you for letting me know.
After checking the game’s screens.rpy file, I’ve identified the problem— The text box image’s file name in a screens.rpy script does not match the one given in the game’s gui folders, causing the game to look for an image that technically is not there.
As I am currently away, I won’t be able to push out a patch immediately, but when I am able, I’ll do so ASAP.