Oh, well if you're running Linux, then good luck - it could be the hardware drivers, the camera drivers, the code controlling the camera. A lot of possibilities.
Hi Mads I ended up sending my STT-603 + FW8G-STT back to SBIG. Bill, their repair guy, made some changes to internal settings and the system has been better behaved since then. Only better, NOT perfect. Whereas I used to see a error 8 almost daily now I only see it maybe once or twice a month. However I have noticed that if I leave the guider running (with an AO-8) without using the main camera then I will most times get an error 8 after an hour or so. Again it does not matter if I used Ethernet or USB. And I still can only get a max of 3.3 Hz with the AO8 using Ethernet. SBIG (and Diffraction Ltd) have never properly addressed this. Best of luck with your STT-8300 Phil