I have run into this same problem recently. It occurred on a couple of RHEL 5 servers where I had XML errors when I attempted an initial update on them. I solved this problem by removing the two RPMs, deleting all of the related files in /tmp, and deleting the /opt/Symantec directory. I re-installed SAV and updated both servers successfully. The -d/--defs and -a options hang (I didn't try any others).
I'm not interested in the Reporter or auto-protect right now. The two required daemons (symcfgd, rtvscand) are running. The defs file confirms the successful update:
[root@eadc-w-sdevdb01 virusdefs]# cat definfo.dat
[DefDates]
LastDefs=20111214.009
CurDefs=20131223.002