For the first issue, refer to the FSL EDDY documentation – the bit where they discuss ‘sampling on the sphere’. To cut a long story short, add -eddy_options "--slm=linear " to your dwipreproc call to silence the warning – although there’s a good chance it won’t make all that much difference.
The second issue is more problematic though. Clearly, your eddy_openmp command is crashing out with a memory access violation (most likely a bug). To debug this one, you’d need to inspect the contents of the temporary folder (you can see its location in your output, it’s probably still there, but if not, invoke with -nocleanup) to check all the inputs to that eddy_openmp command are valid and as the command would expect. If everything looks OK, try running that eddy_openmp command directly within that folder (i.e. copy/paste that line into a terminal, with the working directory set to the temporary folder). If that still crashes out with the same error, then you’d need to refer to the FSL support forum…
This recent thread may also be useful here.