thks for the feedback.
I have just receive this words from Blackmagic Technical support:
We are experiencing some problems with the current drivers and framelink. OSX 10.5.7 is also as yet untested. We are looking into this, but I would suggest to solve the issues at the moment, to roll back to a previous driver version. The framelink workflow is also expected to be superseded by the release of Media Express 2.0.