G'day mcfarnell,

Welcome to the Monastery.

You've put your code within <code>...</code> tags; which is good. Please do the same for data, program output, and error/warning messages. That way, we can see exactly what you're seeing.

After commenting out line 30, the real output would have been:

Perl MySQL Connect Demo
Connected to the MySQL database.
[download]

I don't know what the real output associated with "500 internal server error" is because you don't show it. This is an important piece of information which you should always provide when asking for help.

From the code you show, you've almost certainly got a problem with the format of $DSN. See the various formats shown for DBD::mysql: connect().

You also have potential problems with one or more of the interpolated, double-quoted strings that you've shown as "***". Passwords in particular often contain special characters: "pass$word", for instance, will evaluate as the literal string 'pass' concatenated with the value of the variable $word.