The proc sws_user_proc_staging is meant to be owned by the ctxsys user, which it is when installing it normally because the installation script reconnects as ctxsys before creating it. The import seems to have recreated that procedure owned by your normal database user, instead of ctxsys. Try to drop the sws_user_proc_staging proc in the ctxsys scheme and manually run the block in doc/sql/site-wide-search.sql that is executed as ctxsys (line 958 to 974 on my copy).
This is just a guess though.
