Magento Error

I have a 1.6 install of Magento and I don't recall doing anything that would have broken it (I may have by mistake)

I get this error when logging in as a customer

exception printing is disabled by default for security reasons

In the log file I see this

a:5:{i:0;s:236:"SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND customer_id = 39 AND qty <= 1)' at line 1";i:1;s:7721:"#0

Can anyone help?