Really in need of some assistance here!!!!

My idevice: 3GS iOS 4.2.1 BB 06.15.00 old bootrom

After using the redsnow and ultrasn0w my phone was working fine I installed sb settings and reboot and now cydia will not load sources,changes,or anything and at the top it say downloading release and stays stuck on that.I really need help !!!! Any ideas