BUG: Origin ??. SQL ERROR thrown on database.mysql.inc line 66 - Aggregator2? Taxonomy-Theme? taxonomy.module? Node Delete error

When I try to delete an Aggregator2 feed or feed-item I get an SQL ERROR as follows:

user error: Not unique table/alias: 'tn'
query: SELECT COUNT(*) FROM node n
INNER JOIN term_node tn ON n.nid = tn.nid
INNER JOIN term_node tn ON n.nid = tn.nid
INNER JOIN users u ON n.uid = u.uid
WHERE n.type = 'aggregator2-feed'
AND tn.tid = 2
AND n.type = 'aggregator2-item'
AND tn.tid = 2
in C:\Inetpub\wwwroot\tapenews000\includes\database.mysql.inc on line 66.

user error: Not unique table/alias: 'tn'
query: SELECT n.*, u.name, u.uid
FROM node n
INNER JOIN term_node tn ON n.nid = tn.nid
INNER JOIN term_node tn ON n.nid = tn.nid
INNER JOIN users u ON n.uid = u.uid
WHERE n.type = 'aggregator2-feed'
AND tn.tid = 2
AND n.type = 'aggregator2-item'
AND tn.tid = 2
ORDER BY n.changed
DESC LIMIT 0, 50
in C:\Inetpub\wwwroot\tapenews000\includes\database.mysql.inc on line 66.

Please note that in both cases the lines "INNER JOIN term_node ... etc" are concatenated with no space as follows:
INNER JOIN term_node tn ON n.nid = tn.nidINNER JOIN term_node tn ON n.nid = tn.nid

The whole story:

I am using Aggregator2 with Taxonomy-Theme (a combination that rocks, by the way).

I just discovered that I added the same aggregator2 feed twice, with a different path-alias each time.

I started correcting by deleting one of the 2 feeds, on the mistaken assumption that all the feed-item chldren would be deleted automatically. Mistake!

Now I am deleting the feed items one at a time and getting the error messages above.

Clearly the SQL is malformed, but I cannot identify the point in the code where the bad SQL is constructed.

A scan of the source produces the following locations as suspect sites for the error:

=================================================

tapenews000\modules\node.module(806):
'options' => $terms,
'join' => 'INNER JOIN {term_node} tn ON n.nid = tn.nid');

tapenews000\modules\taxonomy.module(839): $sql =
'SELECT DISTINCT(n.nid), n.sticky, n.title, n.created FROM {node} n
INNER JOIN {term_node} tn ON n.nid = tn.nid
WHERE tn.tid IN ('. $str_tids .')
AND n.status = 1
ORDER BY n.sticky DESC, n.created DESC';

tapenews000\modules\taxonomy.module(840):
$sql_count =
'SELECT COUNT(DISTINCT(n.nid))
FROM {node} n
INNER JOIN {term_node} tn ON n.nid = tn.nid
WHERE tn.tid IN ('. $str_tids .')
AND n.status = 1';

tapenews000\modules\taxonomy.module(846):
$joins .= ' INNER JOIN {term_node} tn'. $index .' ON n.nid = tn'. $index .'.nid';

=============================================

I cannot figure out from where any of these lines would be getting called.

Would sombody more knowledgeable than I please comment?

I have created HOW-DO-I thread at:
BUG!? Aggregator2? Taxonomy-Theme? taxonomy.module? Node Deletion throws SQL Errors

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I dont know of any way to turn on tracing in drupal (sorry, am relative newbie), nor is there anything like a stack trace so far as I can see, nor would I expect one. But that leaves me in the cold for debugging this.

Please HELP !!!!!!!!!!!!!