After running a 'yum update' this morning, I am now no longer able to logon using my user account. I installed Fedora 2 test 1 and this is the first update I have run.

When I try and logon (using gdm) I get a window managerless dialog box saying, "Error! Unable to set executable context". I can logon as root, but not as anyone else. I have tried creating a new account and the same happens.

As root I can 'su' to my non-root users as long as I select 'n' when it asks 'Would you like to enter a security context?'

Searching on google suggest that this is something to do with SELinux, as there are a few hits in source code (for example: ttps://listman.redhat.com/archives/pam-list/2003-August/msg00034.html)

Anyone have any ideas? Your help is much appreciated.

Either update to the latest SELinux packages available in Rawhide (the FC2 development tree) or disable SELinux. You should actually update to the test2 base as well, its housed in the 1.91 directories on the mirrors.

To disable SELinux for a temporary fix, add this to your grub.conf on the 'kernel' boot parameter line (where you see the root=LABEL=/).
selinux=0

Also, you should edit /etc/sysconfig/selinux (create this file if it is not present) and change:
SELINUX=permissive
to
SELINUX=disabled

The correct long term fix is to update the SELinux packages and relabel your filesystem with:
fixfiles relabel

The packages that need to be updated are, policy, policy-sources, setools, setools-gui, and anything that is needed for dependencies on the new packages.

Thanks. Disabling SELinux worked, so I updated and relabeled using 'make relabel' and that seems to have fixed my problems.