Are there any known limitations when using a standalone rowset FILL statement?

We have a mass email process that "should" read in 200,000 records and send out emails. We are  sing a standalone rowset FILL statement to get those 200,000 records. It churns for awhile and then throws this error:

"Unexpected data type code: None. (180,605) N_EMAIL_MSG_WK.N_PREVIEW_BUTTON.FieldChange PCPC:335  Statement:2

The evaluator encountered an unexpected data type code."

The code is this:

Local Rowset &rsEmailQueue = CreateRowset(Record.N_EMAIL_QUEUE);

Local integer &iEmailQueueCount;

&iEmailQueueCount = &rsEmailQueue.Fill("WHERE PROCESS_INSTANCE=:1 AND N_EMAIL_PRCS_ID=:2 AND N_EMAIL_MSG_ID=:3", 15517433, "TEST_ALL", "TEST_GENERIC");

If we add "AND ROWNUM < 200000" to the .Fill criteria, it works. It's like there's a limitation at 200,000.