Christof,
The log file is telling me that our background monitoring service is suffering a GP fault. It started happening on October 20th (presumably the point where you upgraded to Windows 8). This was with IDU version 3.2.6/3.2.7 (which used the same version of the background monitoring service), but continued to happen after you installed IDU version 3.2.8 on February 4th.
We set up a RL board, installed Windows 8.1 and all standard drivers and then installed IDU version 3.2.8. We are seeing no failures. This means that there is something in a bad state as a result of the Windows 7 to Windows 8 upgrade (my personal rule: as painful as it is reinstalling everything, do so; *never* upgrade), or there is something else that needs to be included in the picture in order for us to see the problem occur...
To look into the latter case, I need some more information regarding your configuration and what (else) you have installed. What additional hardware to you have installed? How do you have the BIOS configured? For example, did you use legacy boot or did you use UEFI? Did you secure Windows 8.1? Do you use RAID or SSD caching? If not, did you install the RST driver anyway? If so, what version of RST did you use? What other major software packages and drivers do you have installed?
Thanks in advance,
...Scott