grep, the "DBI::db=HASH(0x838242c)" I think is the result of DBI->connect("dbi:mysql:database=test;host=localhost;user=root;") being printed.

shalomgod, I would change the code like this to fix your error:

my $user = '1'; #or whatever default value you want

print $query->header("text/html"),


$query->start_html(-title => "Database Test"),

$query->h1("Database Test"),

$user = $query->param("username"),

my  $db_handle = DBI->connect("dbi:mysql:database=test;host=localhost;
+user=root;")
  or die "Couldn't connect to database: $DBI::errstr\n";
[download]

I would also definitely recommend using placeholders, like grep said, and taint checking as well. I'd recommend checking out Ovid's CGI course at http://users.easystreet.com/ovid/cgi_course/, most importantly Lesson 3 on security.