PNG plugin problem

Hello..
Thinking of doing a good thing, I got rock solid and I have to say that it does what it promises, but unfortunately I have a problem I can not solve .... If I choose to save the rendering, in particular the various channels and choose format as PNG, finished rendering gives me an error message and does not save the file, however if you manually save the various VIPs channels, the render window, everything works well ... you can well understand that in this situation it is impossible to use Backburner to work and the pc at night, because the files will not be saved ... with all the other formats that are not error .... use 3ds max design 2014 vray 2:40 ...
Some of you have the same problem? How can I solve it?

Thank you all ...

with vray frame buffer does not work,
with 3dsmax frame buffer is ok.

I have the exact same problem with V-Ray and SR 1.5 (V-Ray Frame Buffer)

3ds max design 2014 V-Ray 3.0 Final

Please look into this.

Thanks!

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