instead of downloading an image to the switch.
could you check if you can backup the config via TFTP.
this can help in isolating problem.
Also whats the model number of switch and exos version ur loading.
i understand you can ping the switch from the server.
could you see request coming to switch.
Sometimes it turns out to be a tftp server problem.
Two TFTP severs in the same machine cause conflict and doesnt work.
Can you try from a different machine.
can you provide access?
