Strange behavior with saveWebImage (php/mapScript)

[Murilo Lacerda Yoshida]

  Hi all,
  I recently changed may Server from redHat 8 to debian 3.1 and now is
happening a strange thing.
  First I see a map, zoom and pan it, all ok.
  If I continue to see a few other maps, when I zoom and pan it,
sometimes the image displayed is from a previous map. For example, I pan
my map to the right, and the page displays an image from another map,
and is an image I have seen before.
  Did it happen to somebody in the list before?

  I don't have a clue of what's going on, please help !!
  Thanks,
    Murilo