My final attempt was successful, sort of.
I switched SElinux to enabled and rebooted, then the install worked OK.
Then I had to use a live CD to be able to boot, changed SElinux to disabled, and reboot again.
Then I had to us lpoptions to set the default parameters as the CUPS gui tool refused to change anything.
Phew. What a tortuous route.
Back to sleep now......... 
 
-----Original message-----
> From:Bill Maidment <[log in to unmask]>
> Sent: Wednesday 29th June 2016 16:34
> To: Akemi Yagi <[log in to unmask]>; SL Users <[log in to unmask]>
> Subject: RE: SL7 CUPS/SELinux problem trying to install Brother HL-3150CDN printer driver
> 
> Well I've heard back from Brother and they suggest that my SElinux set up has a problem. They recommended that I do
> semodule -vR
> This gave me exactly the same error messages. Then I did semodule -vB which worked OK, but repeating semodule -vR still gives
> 
> [root@ferguson src]# semodule -vB
> Committing changes:
> Ok: transaction number 0.
> [root@ferguson src]# semodule -vR
> SELinux:  Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version.
> SELinux:  Could not open policy file <= /etc/selinux/targeted/policy/policy.29:  No such file or directory
> /sbin/load_policy:  Can't load policy:  No such file or directory
> libsemanage.semanage_reload_policy: load_policy returned error code 2. (No such file or directory).
> [root@ferguson src]# 
> 
> This is happening on two different SL 7.2 machines with SElinux installed but disabled.
> 
> I even tried uninstalling selinux* but that got me into deeper trouble.
> 
> [root@ferguson src]# rpm -qv selinux-policy
> selinux-policy-3.13.1-60.el7_2.7.noarch
> 
> Is there an issue with this version of selinux???
> 
> Cheers
> Bill
> 
> -----Original message-----
> > From:Bill Maidment <[log in to unmask]>
> > Sent: Saturday 25th June 2016 17:26
> > To: Akemi Yagi <[log in to unmask]>; SL Users <[log in to unmask]>
> > Subject: RE: SL7 CUPS/SELinux problem trying to install Brother HL-3150CDN printer driver
> > 
> > Thanks for the suggestion Akemi.
> > Unfortunately, it made no difference.
> > I'm awaiting comment from Brother, but I suspect they will say change to Ubuntu :-(
> > Cheers
> > Bill 
> >  
> > -----Original message-----
> > > From:Akemi Yagi <[log in to unmask]>
> > > Sent: Saturday 25th June 2016 1:10
> > > To: SL Users <[log in to unmask]>
> > > Subject: Re: SL7 CUPS/SELinux problem trying to install Brother HL-3150CDN printer driver
> > > 
> > > On Fri, Jun 24, 2016 at 2:33 AM, Bill Maidment <[log in to unmask]> wrote:
> > > > Has anyone any suggestions how to get a Brother HL-3150CDN printer driver installed on SL7.
> > > > I have been trying to install using the Brother supplied installation script, which worked OK on SL6.
> > > >
> > > > With SL7 I get error messages such as:
> > > > SELinux:  Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version.
> > > > SELinux:  Could not open policy file <= /etc/selinux/targeted/policy/policy.29:  No such file or directory /sbin/load_policy:  Can't load policy:  No such file or directory
> > > >
> > > > The file in question does exist, but I have selinux disabled anyway.
> > > >
> > > > SL7 is using cups version 1.6 whereas SL6 uses cups version 1.4. Is that an issue?
> > > > I guess the Brother script is a bit out of date as it was created in 2012.
> > > >
> > > > Any help would be appreciated.
> > > >
> > > > Cheers
> > > > Bill Maidment
> > > 
> > > Can you try reinstalling selinux-policy packages and see if that fixes
> > > the issue?
> > > 
> > > yum reinstall selinux-policy\*
> > > 
> > > Akemi
> > > 
> > > 
> 
>