我已经安装了gem：
gem install sdbport -v 0.2.0
并运行以下命令：
sdbport import -k $AWS_ACCESS_KEY_ID -s $AWS_SECRET_ACCESS_KEY -r us-west-1 -n data -i /tmp/test-domain-dump
然后给出以下错误：
/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/lib/sdbport/domain/import.rb:24:in `gets': Is a directory @ io_fillbuf - fd:7 /home/projects/smb/attsp-script/domain-dump (Errno::EISDIR)
from /home/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/lib/sdbport/domain/import.rb:24:in `import'
from /home/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/lib/sdbport/domain.rb:14:in `import'
from /home/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/lib/sdbport/cli/import.rb:21:in `import'
from /home/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/lib/sdbport/cli.rb:26:in `start'
from /home/.rvm/gems/ruby-2.1.5/gems/sdbport-0.2.1/bin/sdbport:6:in `<top (required)>'
from /home/.rvm/gems/ruby-2.1.5/bin/sdbport:23:in `load'
from /home/.rvm/gems/ruby-2.1.5/bin/sdbport:23:in `<main>'
from /home/.rvm/gems/ruby-2.1.5/bin/ruby_executable_hooks:15:in `eval'
from /home/.rvm/gems/ruby-2.1.5/bin/ruby_executable_hooks:15:in `<main>'
请帮我解决这个问题。提前感谢!!