Samsung Galaxy S4 "Prevention Information" USB OTG

I am trying to connect things to my S4 with a USB OTG cable. Standard devices such as mass storage, keyboard and mouse all work fine. My problem seems to be with vendor class devices. I connected an FTDI USB to UART bridge (TTL-232R-3V3) to a USB OTG cable and installed the FTDI app. I plugged in the OTG cable and the phone reccognised the FTDI chip, launched the app, waited a few seconds and then closed the app again. I got the message: "Prevention Information, An application has been forced to stop for an unauthorized attempt to access system in your device". (Including the grammatical error) I have the same problem with my Arduino Uno using the ArduinoDriod app. I tried both devices on a friend's Huawei p6 and they both worked fine. From what I can tell, this issue is specific to the S4 and seems to be related to the recent update to Samsung Knox. Does anyone know of a work around that doesn't involve rooting the device? I am still in the 14 day trial period of the phone, so I could swap it for a different one. How do I tell if the Galaxy Note 3 or the LG G2 will have the same problem?