The server I'm working on is running MySQL 3.23, and I think I may have just run into a problem. Apparently, I'm not allowed the do UPDATE queries that involve multiple tables. The MySQL manual says:
Starting with MySQL Version 4.0.4, you can also perform UPDATE operations that cover multiple tables:
UPDATE items,month SET items.price=month.price
WHERE items.id=month.id;
So, I'm guessing this might be the problem. BUT, what I'm doing is not actually a multi-table update, it's just an update of one table using data from two, like so:
UPDATE search, rebates SET search.rebate = '1' WHERE search.ItemNo = rebates.ItemNo
I'd rather not have to upgrade, if possible, because that will probably introduce a whole new can of worms (and differences between development and public servers)... so if there's a way to do this as a single query, please let me know.