How to run 2 TMPG at once?

[AR3A51]

I got a movie that have 2 parts, I want to do them together so I can burn and watch them together... When I open another TMPG and click "browse" for video, the program launches like 4 errors then shut down (luckily only shut down the non-active one).

[r6d2]

Sorry, cannot reproduce the error. I have always run as many simultaneous instances as I want. I'm using 2.511.

Simultaneous instances running will not encode faster, though, so little is gained if you do.