This  http://localhost:8080/ ./c1.html looks suspicious. At least the space, and did you really configure your local webserver to know the current working directory of your Perl script?

I normally use the file:// protocol (+ absolute path) for simpler HTML pages (your title says "file" not application)

If this doesn't help, fix your Firefox.

edit

To be clear this is NOT a Perl problem. Find a solution from the command line.