Multisite Shared Tables Problem - One Site OK; other gives duplicate entry

BS"D

I have created two sites sharing one database so that user data is shared. At first, I was unable to create content on either site so I was instructed to run the following commands:

update shared_sequences set name = concat('site1_',name) where name not like 'site2_%';

update shared_sequences set id = id + 100;

and this worked. Then, I was on vacation and did not do any further work on the sites except adding but not activating a couple of modules. When I tried to create content on one of them (the one that I had developed first and was working independently before I added on the second site and changed the prefix on some of the tables to shared_) I got the following error message or a variant of it on any content I tried to create:

user warning: Duplicate entry '3' for key 1 query: INSERT INTO menu (mid, pid, path, title, description, weight, type) VALUES (3, 1, 'http://www.millionwordimension.info', 'MillionWorDimension.info', 'Simple List of Words for SEO!', 5, 118) in /home/cybfirmc/domains/millionwordimension.com/includes/database.mysql.inc on line 174.

Yet, on the other site I could create content, including menus, with no problem whatsoever.

Here are the tables I have shared:

$db_prefix = array(
'default' => '',
'authmap' => 'shared_',
'profile_fields' => 'shared_',
'profile_values' => 'shared_',
'role' => 'shared_',
'sequences' => 'shared_',
'users' => 'shared_',
'users_uid_seq' => 'shared_',
);

Sites are http://www.millionwordimension.com and http://www.wordshoppes.com

Any idea as to what could be causing the problem?

Thanks, Itzhak