TwonkySever does not pause (or FF/FR) flac files

I have a problem with my FLAC files, I can not pause them (or FF/FR).
I'm using a Marantz NA7004 connected to my network with a NAS where I installed the Twonky sever 7.0.8. And I control the Twonky server with a app on ipod.
Do you have a solution to solve this problem?

Thanks
Pasca