I'm afraid your out of luck for my pre-compiled version. My kernel is 2.4.18-rmk7-pxa-embedix so the kernel module I have compiled won't work with your kernel : (
I think I ended up cross-compiling the driver (tho' I might have compiled the driver on my Zaurus I can't remember - It was a long time ago)!
Either way I needed (apart from gcc) the kernel source for my Zaurus (the pl2303 driver has been included in the Linux kernel for a while).
*Note* I couldn't get the driver from Prolifics site to compile. I had to use the one that came with the kernel.
There are plenty of tutorials on the net about cross compiling (remember google is your friend) so I won't tell you how to do that!
I found this one very helpful - but it is specifically for the Zaurus.
If you manage to get gcc for your Archos
From your kernel source find the '/linux/drivers/usb/serial/' dir.
within that will be pl2303.c & pl2303.h
to compile them type (as root) 'gcc pl2303.c'
Hope this helps