I use maven 3.0.3 and have tried to generate pom for third-party jar like this:
mvn install:install-file -Dfile=cobra.jar -DgroupId=com.cobra -Darti
I had that error when I was using maven in Windows, what worked for me was opening the cmd and not the PowerShell. Apparently certain errors appear when you don't do it with the cmd. I hope it works.