Receiving multiple subscr_signup emails

I'm using Drupal 4.7.6.

I streamlined the lm_paypal subscription page a little. The site I'm working on has two different subscription options, so I created a page that has both subscription buttons on the same page, along with the buttons that link directly to PayPal. To do this, I copy/pasted the forms from the actual lm_paypal subscription pages and added some PHP code to drop the uid into the hidden "custom" field. I also added the link to the lm_paypal.js file to the page.

After some trial and error, it seems to be working great. People subscribe through my page, PayPal processes it, and they are added to the "subscriber" role. Wonderful.

The problem I'm having is that lm_paypal is sending multiple copies of the subscr_signup email. Like, a dozen so far for each person who subscribed in the past 24 hours. They aren't being charged multiple times, but the ipns page shows that there is a corresponding db entry for every additional subscr_signup that is going out.

A couple of questions... 1) did I miss something when setting up the page (apparently), and 2) how do I get it to stop sending multiple emails/creating multiple db entries?