Been using arduino successfully for about 2 years. I'm also about 80% done building a Reprap Mendel.
In an attempt to get my reprap software working in OSX i've been making several changes to my computer. I installed Windows 7 in "Parallels" and upgrades Java to SE 6 in Windows and my Snow Leopard. Since I've done that, my arduino software quits every time I upload a sketch. I tried to connect a board already setup to do serial.print diagnostic information on boot up of the chip, and when plugged in the serial monitor of my arduino sees the text it spits out. When I upload a new sketch it quits. I had been using Arduino release 21, I just downloaded release 22, which didn't help. I re-installed the FTDI package that came with the new release, which also didn't fix the issue.
I found this post from the old forum site:http://arduino.cc/forum/index.php/topic,26938.msg200256.html#msg200256
that somewhat covers the topic. I saw that this problem was resolved with java preferences, but mine are already: 1st SE 6 64, 2nd SE 6 32. Not sure what to do to progress from here.