Hints:

try using the -t switch, to set the initial TTL (hopcount):

"-t 1-25 (1)Sets initial IP TTL value (target gateway is known to be n hops from the
source host, the TTL can be preloaded to facilitate a faster scan.)"

If you then continue to get hopcount exceeded, you can also tweak the -x switch:

"-x expire vector (1)

The expire vector is the number of hops that the scanning probes will expire, past the gateway host. The binding hopcount is the hopcount of the gateway + the expire vector."