First of all apologies for not being very precise. This mainly stems from the fact that it's really more a CPBackup question than a Dosbox question and I just wanted to know if someone has already successfully used it.
For those who are interested, I will describe the problem in more detail. I found some old disks with CPBackup files named CPBACKUP.001, CPBACKUP.002 and so on. I don't know the version of CPBackup with which I created these files but since they are from around 1993 I guessed that they were created with CPBackup from PC Tools 8.0.
I first tried to read the files mounting a directory as floppy type under Dosbox (gulikoza's CVS from 01/29) with CPBackup V6 (not PC Tools 8 ). After reading the first floppy disk CPBackup asks for the last disk so I replaced the file in the mounted directory with the file from the last disk and swapped the image with Ctrl-F4. But CPBackup doesn't acknowledge the last disk and simply continues to show the dialogue prompting for the last disk.
Interestingly, the exact same problem occurs when using CPBackup under real DOS (Win '98 ). Though unlikely I speculated that CPBackup requires a lower DOS version because of some obscure way it talks to the floppy.
Since floppy didn't work I also tried to restore from a fixed disk. I tried copying all the files into the respective directory as well as copying and reading the files with CPBackup one by one. But CPBackup didn't recognize the files as backups and stated it couldn't find the backup directory.
I also used different versions of CPBackup (from PC Tools 8 and an earlier version) but they showed the same problems. The last thing I tried was placing the files in directories as DosFreak proposed. But that didn't work either.
DosFreak, it would be nice if you could tell me exactly which version of CPBackup you used since using directories of the form DISK1, DISK2 and so on didn't work with my versions.