NOTE: THIS METHOD IS FOR PEOPLE WHO CANNOT USE CYDIA, E.G. UNABLE TO REMOVE TWEAKS FROM WITHIN CYDIA ITSELF. IF YOU CAN VIEW ALL YOUR INSTALLED TWEAKS INSIDE OF CYDIA, THE EASIEST METHOD IS TO FIND THE TWEAK YOU LAST INSTALLED THEN CLICK ON MODIFY, AND UNINSTALL. I just found the solution to this problem, because I was having this issue, and didn't want to have to restore. I am going to explain the process of how to fix it without needing to re-jailbreak:
First, go to: /Library/MobileSubstrate/DynamicLibraries inside of iFile / iFunbox (if you do not have iFile installed, I HIGHLY recommend you get it from Cydia once its working again)
Remove the file called: zenonia_5.dylib or the name of whichever tweak you LAST installed before this issue occurred
Open iCleaner (or iCleaner Pro) and enable Cydia , Cydia sources & Unused dependencies and click on Clean (and restart/respring)
OPTIONAL (RECOMMENDED):
I really REALLY recommend you remove the Hack Your iPhone REPO from within Cydia BEFORE you do ANY of the above