This bug is similar but not identical to this bug. When I try to import this feed, Aggregator2 spits out these errors when Create GUID for items is checked:

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/02/01/po-bronson-autho' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/574/feed', 'affiliate-programs/between-the-lines/2006/02/01/po-bronson-author-of-why-do-i-love-these-people-honest-and-amazing-stories-of-re/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/02/23/andrew-weil-auth' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/577/feed', 'affiliate-programs/between-the-lines/2006/02/23/andrew-weil-author-of-healthy-aging-a-lifelong-guide-to-your-physical-and-spirit/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/03/09/bruce-feiler-aut' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/579/feed', 'affiliate-programs/between-the-lines/2006/03/09/bruce-feiler-author-of-where-god-was-born-a-journey-by-land-to-the-roots-of-reli/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

warning: Cannot modify header information - headers already sent by (output started at /home/.desiree/gapn/gapodcastnetwork.com/includes/common.inc:383) in /home/.desiree/gapn/gapodcastnetwork.com/includes/common.inc on line 191.

And these errors if Create GUID for items is unchecked:

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/02/01/po-bronson-autho' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/581/feed', 'affiliate-programs/between-the-lines/2006/02/01/po-bronson-author-of-why-do-i-love-these-people-honest-and-amazing-stories-of-re/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/02/23/andrew-weil-auth' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/581/feed', 'affiliate-programs/between-the-lines/2006/02/23/andrew-weil-author-of-healthy-aging-a-lifelong-guide-to-your-physical-and-spirit/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry 'affiliate-programs/between-the-lines/2006/03/09/bruce-feiler-aut' for key 2
query: INSERT INTO url_alias (src, dst) VALUES ('node/581/feed', 'affiliate-programs/between-the-lines/2006/03/09/bruce-feiler-author-of-where-god-was-born-a-journey-by-land-to-the-roots-of-reli/feed') in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

user error: Duplicate entry '26-581' for key 1
query: INSERT INTO term_node (nid, tid) VALUES (581, 26) in /home/.desiree/gapn/gapodcastnetwork.com/includes/database.mysql.inc on line 66.

warning: Cannot modify header information - headers already sent by (output started at /home/.desiree/gapn/gapodcastnetwork.com/includes/common.inc:383) in /home/.desiree/gapn/gapodcastnetwork.com/includes/common.inc on line 191.

I tried applying the patch RobRoy mentioned here, but still get the same result. I have 15 other feeds, and none of them give back this error (though some required me to check Create GUID for items before they worked right). I've tried both the 1.3.1 and 1.3.2 versions of aggregator, patched and unpatched.