Thank you very much for your tips.
> I also had problems and solved it by changing the default configuration that handles virtualbox:
I don't know if it is default or not, but with the same config (or even worse) I installed and ran Windows XP, Vista, Ubuntu 32-bit and 64-bit, Fedora and it worked fine. I don't see any reason why LMDE should be exception -- except one thing, there is something wrong on LMDE side.
> first try installing from the iso and not from a cd.
Already done (I never burn CD).
> Second, be sure to choose debian system.
> 1 .- ram increase it to 40% of which have (real)
Better than this, but if RAM is not sufficient for LMDE installer it should report that fact, and not fail in the middle of installation process.
> 2 .- 3D acceleration enabled
I don't see how this is relevant to copying the files, but I turned this on, and it didn't make any change.
> 3 .- sure to allocate at least 8 gb of disk space
More than this.
> 4 .- increases the amount of video at 128 mb
Again, no relevance for me, and it didn't help.
> enable I/O cache for virtual disk driver:
Ok, it didn't help though.
However I found the culprit -- when you wrote about resizing this and that -- I thought of root partition, it was way to small (how the previous version fitted there, it is a mystery).
So the conclusion is:BUG: LMDE installer does not check the size of the target partitions.
Thank you for hinting me in the right direction