I just had to uninstall the physx that came with KF2 and install this version:
http://www.nvidia.com/object/physx-9.15.0428-driver.html

Now it works fine!

-------------------------------
|  CONTACT INFO  |
-------------------------------
Questions, requests? Contact me at:
(From most prefered to least preferred)

1) TeamSpeak:   iaminfamous8.typefrag.com:9715
2) Steam:   masterrambo65
3) Origin:   -IAM-MasterRambo
4)Twitter:   @IAM_MasterRambo
5) Facebook:   http://on.fb.me/1KRfnka
6) google plus:   google.com/+phazondude117
7) Skype:   iam_master_rambo