Some cameras models can't handle intensed lightings as they are poorly design (optics and/or process). Check Sony if they have Firmware updates for that Pink banding issue you're having.
Unless a firmware that fixes the problem hasn't been issued then you will just have to recompose your shoots to minimize pink banding untill the fixes come out.
The link here usually a place to find for firwares.
http/www.cameratown.com/firmware/index.cfm/hurl/mfg%7CSony
Obviously Sony did not make firmware for that camera, yet.