After the update I had the same problem. What I did was make sure you unzip the new update into your iPhone mod folder. Then run jail break. Make sure and follow the instructions from the ringtone tutorial to a t. Make sure to power off. Then unplug from computer and plug back in and then start pressing the sleep/wake button and the home button at the same time. Make sure to hold them down until the iTunes triangle pops up.
Basically follow the instructions to whatever tutorial you used the first time you modded.