I'm sure you've gotten this figured out by now, but I thought I'd just add something.

There are two tables in your database, and the id's must match. Either the id's got changed, or a table row got deleted in one of them.

Match the 'id' column from table 'jcow_accounts' to...
the 'uid' column in table 'jcow_pages'.

If one of them is missing (probably the _pages), then make a new table row to accommodate the other one. If 'jcow_pages' does not have a column with the same 'uid' in it, then you'll have to create a new table row in 'jcow_pages' using the same 'id' as the row in 'jcow_accounts'. If the 'uid' got changed in 'pages' then you'll have to make both 'uid' and 'id'(from 'accounts') the same.

The bottom line is that 'uid' in 'pages' must match 'id' in 'accounts'.

Hope it helps someone anyways...