I had the same problem.
You have to setup a user with password on your Windows PC. Next set a directory as shared and call that directory from sbmfs.
Type in CLI:
run AmiTCP:bin/SMBFS Workgroup=[Name of your Windows Workgroup] User=[Username you setup on your Windows PC] Password=[Password you setup on your Windows PC] Service=//[Name of your Windows PC]/[Name of the shared directory]
Replace the stuff between [] with the apropriate entries. Give short names without any spaces.
I.e.: run AmiTCP:bin/SMBFS Workgroup=WERKGROEP User=Me Password=whatever Service=//MyPC/Temp
