I think you have an optimization/performance problem.
can you please tell us the specific version of Postgres and operating system you are using?
If you can also post your postgresql.conf ( usually inside $PGDATA) it may help
Can you evaluate the execution time of the 3 separate Select Into statements using psql interactively?
Also try to PREPARE the query before actual execution.
If they execute interactively in a timely manner, you have some other problem..
If they don't, then verify that you have table indexes for source_host in table crawled_urls, and for host_name and letype in table rcColinkeeHost.
If those fields are not indexed create indices for them.
Finally, if you are running this on a Pentium-200, just do a hardware upgrade ;-)