I just downloaded (1.6.1). After dismissing the tips page,
I kicked around in the menu bar. When I came to Tools,
I either clicked on Run Plugin or Run Last Plugin (I'm not
sure which). Up comes the calendar control. When I
dismissed it, I got the GPF. After rebooting, I tried both
menu options with no prob. I have not downloaded any
plugins. My bet is that somebody who is developing has
the calendar widget in their plugins and is checking for a
var that has a pointer to it. Therefore, when somebody
does not have the calendar plugin, they get the GPF. My
suggestion: check for the plugin before you try to run it.
Only a guess tho.