As a general debugging approach, print out the lines before giving them to the shell, so you see whether your values in @array have the values you think they should have:

# don't use a C-style loop
for my $i (0..$#array1) {
    my $cmd = "curl -G -x $array1[$i]:$array2[$i] http://www.google.co
+m";
    print "Running [$cmd]\n";
    system( $cmd ) == 0
        or warn "Couldn't run [$cmd]: $!/$?";
};
[download]