Arduino - Com port error - MsPorts.dll 0x00006e87

Hello all, I've been trying to communicate with an arduino for a while now (For those who know arduinos, I am using an arduino ethernet with the USB2SERIAL LIGHT attachment which allows for serial communications). 99.99999% of the time, it's plug in arduino via USB, install drivers, and everything works fine. That's how it has been for me. However, I have recently been getting an error...