You can find out what your version of Perl is with the  -v (lowercase v) command line switch:

c:\@Work\Perl\monks>perl -v

This is perl 5, version 14, subversion 4 (v5.14.4) built for MSWin32-x
+86-multi-thread

Copyright 1987-2013, Larry Wall

... more stuff ...
[download]

The  -V (that's uppercase V) switch will give much more info, but you don't need that for now. See all the command line switches in perlrun.

(And BTW: I hope you aren't running Perl version 5.5!)