Previously using Ubuntu, I never ran into this issue, but using openSUSE I couldn’t get logged into a Samba share using any user accounts. Turns out, the users have to be added to Samba seperately. Ubuntu probably did this through the adduser (useradd?) script. In openSUSE, you have to add the user manually.
You can either use pdbedit, or smbpasswd. Both work.
I won’t give examples here, as using –help for either program will spit out very useful and non-confusing examples. But, that’s how.