"When I change the query to pull less data, I don't get this error."

Sounds like the problem I was having earlier where my program would grow to insane sizes even though I thought I was fetching individual rows. The truth is, I was downloading the entire query into some DBI driver loading zone, and was fetching rows from there.

Check with your DBI driver to see if you can switch it to an incremental method. kschwab was helpful in pointing out how do to this in MySQL.