I just wish to add that DVD-RAM support will be added to InCD 4 soon. Oups, I did a spoiler.
But here, the problem seems to be a software bug rather than a data-corruption error from the device. As I can't help with InCD 3.5 but I can do it for InCD 4, I suggest to give a try to version 4.
Btw, to reply to the original question of "Success in Using Your DVD+RW disc Just Like a HD?", I confirm that myself I have been able to copy 4 Gb of various data to a DVD+RW using a automatic tool with data verification after writting. The copy-compare-delete-copy again test ran several days without error before been manually interrupted.