practically the same happened to me. I installed preloader with System Menu 3.3E, and now the system files are corrupt.
Since preloader is installed, I can run into the HBC, and I have a BootMii NAND backup in my SD card, from right after I installed the HBC.
Since this is not my Wii, but a friend's Wii (mine had 3.2 so no problems), I am really afraid on how to proceed next.
If I install another system menu like 3.2, could the preloader be uninstalled during that process?
Also, if I backup using BootMii (from the HBC), I suppose that by reseting the NAND the preloader will get erased. Is there any change that the backup might fail and I end up with a totally bricked Wii?
I installed preloader right away to be carefull, but it appears that it actually broke my system.
Thanks in adance for any help,
hugo