Need help with samba smb.conf

I have a pretty serious problem as my users won't be able to get to shared drives tomorrow unless I solve it. I've upgraded to Slackware64 14.1 kernel 3.10.17 and samba version 4.1.0.

Previously I was running samba 3.5.8. With the older samba I was able to let Windows users mount specific shares without specifying a password. I had (and still have) a 'guest' user configured in /etc/passwd. Here's the old smb.conf file that used to work under samba 3.5.8:

[global]

netbios name = WEBSERVER
   workgroup = WORKGROUP
   server string = HPRS webserver Samba Server

   security = share

   hosts allow = 192.168.0. 127.

load printers = no
printcap name = /dev/null
printing = bsd
disable spoolss = yes

guest account = guest

   log file = /var/log/samba.%m

   max log size = 50

   passdb backend = tdbsam

   socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192

   dns proxy = no

[xfer]
comment = OHPRS ACH and Enrollment file transfer folder
path = /home/ohprs/xfer
public = yes
guest ok = yes
guest only = yes
writeable = yes
browseable= yes
printable = no
create mask = 0660
directory mask = 0771

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With the new samba 4.1.0 I had to change "security = share" to something else, so I used "security = user". Maybe that's part of the problem. Otherwise, the smb.conf file is unchanged from when it worked under samba 3.5.8.

Need help. How can I let users mount this sharepoint without entering and ID/password?