Tak czy siak nie jest to blad w instalatorze. Problem jest tylko na komputerze, niektorzy ludzie maja taki problem, ale nie jest to zwiazane z programem ktory tworze.
No, never uninstall, unless you want to never come back to this modpack.
Just launch it and pick desired carousel rows from the menu. Then install like usuall.
If you are installing XVM, then you have to select in the modpack how many rows you want to see, the game feature to display 2 rowed carousel is not working in XVM.