[closed] Doing timestamp comparisons with "modified"

I'm getting weird results from trying to do queries based on the last modified time of work items. Here's a code snippet where I add the timestamp comparison into my Term (which contains other field comparisons as well, and seem to work fine):

///////////////////////////////////////////////////////

IAuditableClient auditableClient = (IAuditableClient)
getRepository().getClientLibrary( IAuditableClient.class );

IQueryableAttributeFactory factory =
QueryableAttributes.getFactory( IWorkItem.ITEM_TYPE );

IQueryableAttribute recAttr = factory.findAttribute(
getProjectArea(), IItem.MODIFIED_PROPERTY, auditableClient,
null );

Timestamp timeStamp = getLastPollDate();

AttributeExpression recExpr = new AttributeExpression(
recAttr, AttributeOperation.AFTER, timeStamp );

term.add( recExpr );

///////////////////////////////////////////////////////

The problem is that the "AFTER" comparison seems to always be true no matter what timestamp I use (i.e., a time before or after the actual "modified" value of a given work item). In fact, I can change that operator to "BEFORE" or even "EQUALS" and I always get the same list of records as if I didn't even add this expression into the term. The only way I don't end up getting any records back is with the "NOT_EQUALS" comparison...which doesn't make any sense at all to me.

Note that the Term was originally constructed with Operator.AND.

So, how do I query work items whose last modification was after a certain date/time?