Also check your bios settings ( the basic computer settings).... many motherboards allow you to assign or disable onboard serial ports, or assign them irq settings, which will affect the ttyS* numbers.

Additionally you can test the availability of ports without the perl module,

open(PORT,"+>/dev/ttyS1") or die "Couldn't open serial port\n";

# etc etc
[download]

If you have some spare diskdpace, and can take the time to setup a dual boot, try a full-featured OS like OpenSuSE. I found that it is the best at finding and setting up hardware.

You might also want to look in your /dev after booting and see what ttyS* links there are. Some distros do it differently, they may be real devices or links to some subdir like tts/*

Finally if you don't get the chipset recognized, because it is uncommon, or your distro didn't make a module for it, you can do an lspci (assuming it's a pci card) or hwinfo, etc., to get a list of the chipsets. Then you can google for the kernel patch or module to enable that chipset.