Don't worry - PHD2 can be a bit cranky. Lots of people guiding with the iExos-100.
The EXOS-2 w/PHD2 can also throw the "star did not move enough" error, and I may have a solution, but the weather where I am has been poor for a long time and I've only done limited testing on it - wondering if Wes had a chance to try it. I expect that if it helps an EXOS-2, it'd probably help an iExos-100 as well.
I'd passed you that PHD2 change: Brain/Advanced->Guiding->"Advanced" button->Detailed Calibration Parameters-> Calibration distance, px" (was 25, updated it to 50)
Did you have a chance to try that? Worked for me when I tried it, but the weather hasn't let me out for much testing since...
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras: Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer: Thinkpad x230, Win7Pro/64