MailTo, Lotus, and IE7

Windows Vista, Lotus Notes 7, Internet Explorer 7

When I click on a MailTo link while in IE7, I was hoping it would open a new memo in Lotus Notes (our email client). However, this doesn’t happen. It flashed black & white, like a strobe light. It opens an insane number of windows (60+) before stopping. I seem to be able to right click on the IE group at the bottom and “close group”, but more still come.

I’ve checked that Lotus Notes is set as the default mail client.

Any suggestions as to why this would be happening?

I haven’t updated to IE8 or IE9 yet because some of the things I do are not compatible with IE 8/9.