I believe Earlack is correct: the trial license countdown begins with the first activation, not for each installation. Even after expiration, you can still use nearly all the features though, you just can't save the results. That's pretty common for evaluation software.
(Just curious, does movie output get disabled too? Or just mocap output?)
If you want to test some sample iPi mocap data for other programs, I believe there are files you can download from the website. Also, I posted sample .bvh, .dae, and max files here for others to test:
http://newtek.com/forums/showthread.php?t=101917&page=14Scroll down to message #198. If you learn anything interesting from these files, please post the info in these forums.
Hope this helps.
(Now that I'm thinking about it, I think I"ll upload the test data here later today. I haven't been able to do much testing here lately, so I don't mind sharing my data if others can test it too.) :)
G.