[LAU] large .wav file in Ardour - problems

Hello, I made a large recording in Ardour. The .wav file is 4.9 gb. I'm having problems with it and I don't understand if the file is faulty or if it's something related with the wav format, which seems to have some problems with large files (or am I wrong?). I suspect it could be faulty because the recording in Ardour actually went on untill there was no more disk space, at which point it obviously stopped. So maybe there could be something wrong in the header? The symptoms are: in Ardour (2.8.11 BTW), with a "small" zoom (such that I can see all 5 hours of recording in one screen), I can see the contour of the waveform only to a certain point, at approx. 1h 30m, and thereafter only silence. Strange thing number one is, if I zoom in, at a certain point the waveform appears also for the second part. Strange thing number two is whenever I move the transport bar to a part of the region in the "fake silence zone" and hit play, the transport starts moving from there, but the audio is actually playing *from the beggining* of the region (so more than 1h and 30m before). If I pause, move the transport bar and hit play, the audio now starts from where it had left... Strange thing number three is that strange thing number two stops happening if I put the transport before the 1h 30m point, hit play, and go through that point (after which I hear silence) Do I have any chances of getting back the whole audio file? BTW I tried opening the original .wav with mplayer,vlc,audacity and mhwaveedit and all see the file terminating at that critical point. Also, what precautions should I take in the future when I'll have to record such long sessions? thanks for any help, renato