I think bug in VICE.
emu crashes at random intervals, when i have a joypad attached.
*not script related.
to confirm problem try running this batch file.
x64sc.exe -default -joydev1 4 -joydev2 5 -controlport1device 1 -controlport2device 2
if that fails then it's a vice bug or broken joypad.
can you setup two joysticks manually from GUI?.
if not, please also report the bug to the vice team.