Here is how I got it to work on Win7.
SMB Sharing - the secure way
1) Type "Win+R", then "compmgmt.msc" (this'll open Computer Management).
2) Expand "System Tools", then "Local Users and Groups". Right-click on "Users" and choose "New User..."
3) Define "User name" and "Password" (I recommend using "wii" as user name).
Untick the "User must change password at next logon" box.
Tick the "Password never expires" box.
Click create, then close.
4) Right click on the newly created user "wii" and select "Properties". View the "Member of" tab. Delete "user" from this list. Then click ok.
5) Don't close the window "Computer Management"
6) Open "Local Security Policy" by typing "Win+R", then "secpol.msc".
Extend "Local Policies" and click "User Rights Assignment"
Double click the "Access this computer from the network" policy.
Click on "Add User or Group". Type in "wii", then click ok. You can now close the window "Local Security Policy".
Creating a Share with Computer Management
7a) Activate the window "Computer Management".
Expand "System Tools", then "Shared Folders". Right-click on "Shares" and choose "New Share".
Follow the instructions (browse to the folder you want to share). On the next page, type in the "Share name".
On the next page, choose the option "Customize permissions".
Click on "Custom...". Remove the User "Everyone" and add the User "wii". The permission "Read (Allow)" should already be ticked for the user "wii".
Click on "Finish".
Creating a Share with Windows Explorer
7b) In Windows Explorer, click on "Tools", "Folder Options". Activate the "View" tab. Find "Use Sharing Wizard" and untick it. Close Folder Options.
Navigate to the folder you want to share. Right-click it and choose "Properties". Activate the tab "Sharing".
Click on "Advanced Sharing...". Tick "Share this folder". Type in the Share Name.
Now click on "Permissions", remove the User "Everyone" and add the User "wii". The permission "Read (Allow)" should already be ticked for the User "wii". Close all windows by clicking on OK.
Hope that helps a bit.