Let me guess... You are trying to install Rose::DB from the command line like this:
cpan install Rose::DB
What happens here is that CPAN tries to install a package called 'install' and then it tries to install a package named 'Rose::DB'. junoscript-perl comes with a package called 'install' so you are trying to install junoscript-perl, and that is failing.
So what you are seeing is not a Rose::DB problem, but a cpan usage problem and a junoscript-perl problem. Try it like this instead:
Here are some other people who have discovered the same annoying side-effect...