I have experienced somewhat the same problems. I have installed Samba aswell, but haven't been able to get as far as you. I can ping my PC from my Amiga and the other way around, but that's about it.
I use SMBFS found on
www.amigasamba.org to access my PC drives from my Amiga. I can only mount one device, but since I keep most of the stuff on D: it doesn't matter that much :-) If I transfer large files, I often have to reset and start again. My computer also just stops, in fact I don't even think the file transfer starts.
Sometimes it helps to rename the files, so the filename isn't larger than 30 character + 3 characters in the extension (.zip, .rar, .jpg etc) Also don't allow the screen saver to kick in, as this sometimes blocks my file transfer, but I think it's because of this {bleep}ty Acer laptop.
I don't think the above has any real value, but maybe it will help you out.