As far as I understand the Click2Speak and Optikey softwares are implemented using the EyeX Engine API, so they do require the EyeX Engine to be running for them to function with the eye tracker. The problem then is that when the EyeX Engine is running there is a problem with the tracking, possibly due to interference with the PC Eye Go software running on the machine. There is no driver that can solve this problem since its cause is higher up in the software stack.
It would be interesting to know if the problem with the tracking on your system originates from the EyeX Engine Screen Setup or from interference between the runtimes. How is your PC Eye Go device placed relative to the screen? Is it positioned and angled like in this pic, or mounted in some other way?