I bet you have the not updated version of panel tweaks installed, because you are not the first one that happened to. Have you tried to remove that and try again? If that is it, get the new version of the mod and everyting should be fine.

Btw. that is not a bug, but a mod incompatibility.
Before patching, you always have to remove your mods (except texture mods) and get the updated versions.

As Audrey has already informed you, this is caused by an incompatibility problem with one of your installed mods. Both HUD Tweaks and Panel Tweaks have recently been updated to work with the latest patch for the game.

As a rule, whenever you run across an error, first try uninstalling any mods you might be using. If the problem goes away then, try loading the game up again, testing the mods out by adding them one by one, and you'll eventually track down the culprit.

Thank you for you guys. You help me a lot.