I guess you are running .lrn 2.1. If it's the case then you should get theme-selva from HEAD:
cvs :pserver:mailto:anonymous@cvs.openacs.org:/cvsroot co theme-selva
The version on oacs-5-2 branch is to run with .lrn 2.2. The table "dotlrn_site_templates" does not exist in previous version, that's why you got the error.
cvs -d :pserver:mailto:anonymous@cvs.openacs.org:/cvsroot co theme-selva