Hi,
Sorry to hear your trouble in getting 3DNA up and running on Window 10 using Cygwin. The error seems to be related to the environment variable X3DNA being set to the bin directory by mistake. Try to remove /bin from the end, as shown below, and report back if that works.
export X3DNA=/cygdrive/c/3DNA/x3dna-v2.3
# no /bin at the end
Best regards,
Xiang-Jun