Some newbie help, if you please.

I am trying out macdive and have installed it on my 2011 MBP (Lion). I installed the drivers for customidea USB cable for my Suunto Vyper Air Black. Installed the trial version from the website today (v2.1.5).
I tried downloading some dives from the suunto (I realise the trial is limited to 5 dives). During download of the second dive, macdive crashed. I re-opened it, but is crashed again (I wasn't downloading anything that time). Both times i had pressed the green maxmise button; I dont know if that was a coincidence.
Does anyone have any suggestions as to what might be causing this?
Regards
Charles