Cuda, I'm having the same issue as you but I have not yet converted. My blank login page resulted in me trying to set-up my SSL. I think I messed it up pretty bad. only changed the configure files in admin/include and include/. When it didnt work properly, I changed the files back to the originals but I'm still getting the blank admin page.
Will I lose my products and settings if I re-upload zen-cart?
Do I have any options to fix this?
I am using 1.3.9g



