Hi Wei,
You are getting this message because in your system the environment variable FSLGECUDAQ is not set. It is set if you run the configuration script (fsl/etc/fslconf/fsl.sh).
This variable contains the name of the CUDA (GPUs) queue. I have already changed the code (for next version) to do not produce the message in case that the variable is not set.
You can ignore the message (the script continues despite the message) or set the variable if you want to avoid the message.
If you want to set the variable, you can:
1. Execute the configuration script fsl/etc/fslconf/fsl.sh
2. Or Set it by yourself: export FSLGECUDAQ some-value
Best,
Moises.