Audio sync problems Connect recording download in Premiere

Hi

We are recording series of live webinars in Connect. We can download in MP4 format onto the hard drive. However we would like to further edit these in Premiere Pro. All imports into premiere show audio synch problems on import. Think this might be a variable frame rate issue I have tried to run it through Handbrake to convert to constant bitrate before import but seems not to make any difference.

Any ideas?