fuser error message: Invalid argument

Hello,
I'm trying to use fuser but I only get errors:

# ll /tmp
total 16
drwxr-xr-x   2 root     sys          178 Jun 13 12:26 hsperfdata_root
-rw-r--r--   1 user1    staff          0 Jun 13 12:33 test

# fuser -c /tmp/test
/tmp/test: fuser: Invalid argument

Could you, please, advice?

PS: It's an s10u10.

Thanks in advance,
Carlos.