well, if there is no disk in in D:\ then this error might creep up. OR does this happen also when you have a dsik in D:\?

It happens when there is no disk in drive D:.

But that's not the point: the point is that the program is not supposed at all to check whether there is disk in drive D or not, and not to give this error message. It never did on my old computer.

Or maybe is it because drive D is of dvd, not cd drive?

why shouldn't the program check the disk ?
afterall you are ordering it to do so with the mount command ?

Well, if you don't want Dosbox to check the drive, then don't mount it. I don't mount my CD-Rom drive unless I need it.
You could handle this with a small batch file in your c:\games.
Call it dvd.bat (cd.bat is NOT a good idea 😀) with just
mount d D:\ -t cdrom -usecd 0 -ioctl
in it.
So when you need the DVD, just call that batch. For games that need it from the start, just remeber to pop the CD-Rom in before starting the batch.

Yes, that's what I did - I deleted that line of mounting drive D from the config file. 😀

But still, of curiosity, I would like to know what exactly is the source of the problem here - whether it has to do with dvd drive or whatever, because that never happened on my old computer - whether there was disk in drive D or not.

Does it really say "insert disk?" Shouldn't that be "disc"?

Disc, disk, what's the difference? 😉 the contents of the error message is what important, not the spelling.

And which OS did you have on the old computer?

Rick wrote:

Disc, disk, what's the difference? 😉 the contents of the error message is what important, not the spelling.

http://docs.info.apple.com/article.html?artnum=302152

😀

By OS do you mean which Windows, or FAT32/NTFS? I had the same OS as on my new computer - windows XP (SP2), NTFS.

How do your start DOSBox? With a front-end application, a short-cut, drag-and-drop, or from the CMD.EXE prompt?

cd/dvd burners also behave a bit different by times, but the whole thing
is nothing dosbox specific.