The C code calls Drand01() to initialise the hash seed. However, it is returning 0 for some reason. Drand01 is a frontend macro to the system random number generator -- which one, I have no clue. You could look at Perl's configure output to figure that one out.
This method is only for randomising the hash seed. It might not be critical for the installation. If you plan to make Perl user-accessible (e.g. a web service), you might run into a denial of service attack at worst. And, indeed, you can "fix" that with the aforementioned environment variable.