WebDav issue

I’ve set up a webdav folder and I can connect to it. It mounts in Finder under OS X 10.3.9. But when I try to move a simple image file it gives me an error message saying:
“You cannot copy some of these items to the destination because their names are too long for the destination. Do you want to skip copying these items and continue copying the other items?

When I press continue, it copies files with 0 size. The names are in fact normal like picture.jpg, not long at all. What could be the issue here guys?