Dear friends:
Without any intervention or modification on my part, yum now works fine,
both as user and root. Perhaps the problem was at Dag's end, not mine.
[sher@localhost ~]$ yum list available |more
Setting up Repos
Reading repository metadata in from local files
Available Packages
3ddesktop.i386 0.2.8-1.2.el4.rf dag
4g8.i386 1.0-1.2.el4.rf dag
BasiliskII.i386 1.0-0.20050322.2.el4.r dag
Canna.i386 3.7p3-7.EL4 sl-base
Canna-devel.i386 3.7p3-7.EL4 sl-base
Canna-libs.i386 3.7p3-7.EL4 sl-base
ElectricFence.i386 2.2.2-19 sl-base
FreeWnn.i386 1:1.10pl020-5 sl-base
FreeWnn-devel.i386 1:1.10pl020-5 sl-base
FreeWnn-libs.i386 1:1.10pl020-5 sl-base
Hermes.i386 1.3.3-4.2.el4.rf dag
Hermes-devel.i386 1.3.3-4.2.el4.rf dag
Thank you all for your help.
Benjamin