What "bad list v: No such file or directory at -/usr/libdata/per15/OpenBSD/Pkg_Add.pm line 1115" means?

I recently installed OpenBSD on an old laptop from 2005 and I am trying to install nano and then xfce4 and then a few other programs, but every time I try to use pkg_add, I get the message:

Fatal error: bad list v: No such file or directory at -/usr/libdata/per15/OpenBSD/Pkg_Add.pm line 1115