I don't know why, but I transfer just the left audio with my firewire cable in my pc.

My firewire card is Pyro.

With the USB cable I have no problem.

Can anyone help me?

Just had the same problems right in front of a client.

Using a Matrox RTx100 and Premiere Pro

Left audio was auto on the camera's mic.

Right audio was manual with an externial AD shotgun mic.

The pdx-10 is known to have an issue with stereo transfer. This has been discussed previously, for example here:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=25252

Sony is of no help.

This is a known problem but it is not really Sony's fault (although they would be cool to mention it in the manual). This cam can set a parameter that indicates it's audio is dual mono instead of stereo and Microsoft's Windows Firewire driver does not interpret that correctly. So guess who's fault it is...

If you use a program that doesn't use the Windows Firewire driver for capture or use a Mac (you know, the computer made by the guys who invented Firewire) you will not experience the problem.