[root@localhost ~]$ cat /etc/yum.repos.d/fedora-core.repo
[core-dvd]
name=Fedora Core 6 - i686 - DVD
baseurl=file:///mnt/dvd/
enabled=1
gpgcheck=1
gpgkey=file:///mnt/dvd/RPM-GPG-KEY-fedora

[root@localhost ~]$ cat /etc/yum.repos.d/fedora-extras.repo
[extras-dvd]
name=Fedora Extras $releasever - $basearch
baseurl=file:///mnt/dvd/
enabled=1
gpgkey=file:///mnt/dvd/RPM-GPG-KEY-fedora-extras
gpgcheck=1

[root@localhost /]# yum clean all
Loading "installonlyn" plugin
Cleaning up Everything
[root@localhost /]# yum makecache
Loading "installonlyn" plugin
Setting up repositories
extras-dvd                100% |=========================| 1.3 kB    00:00     
core-dvd                  100% |=========================| 1.3 kB    00:00     
primary.xml.gz            100% |=========================| 772 kB    00:00     
################################################## 2242/2242
primary.xml.gz            100% |=========================| 772 kB    00:00     
################################################## 2242/2242
filelists.xml.gz          100% |=========================| 2.4 MB    00:00     
################################################## 2242/2242
filelists.xml.gz          100% |=========================| 2.4 MB    00:00     
################################################## 2242/2242
other.xml.gz              100% |=========================| 5.9 MB    00:00     
################################################## 2242/2242
other.xml.gz              100% |=========================| 5.9 MB    00:00     
################################################## 2242/2242
Metadata Cache Created
[root@localhost /]# yum install kdebase
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for kdebase to pack into transaction set.
media://1161131669.029329%232/Fedora/RPMS/kdebase-3.5.4-12.fc6.i386.rpm: [Errno 4] IOError: <urlopen error unknown url type: media>
Trying other mirror.
Error: failed to retrieve Fedora/RPMS/kdebase-3.5.4-12.fc6.i386.rpm from core-dvd
error was [Errno 4] IOError: <urlopen error unknown url type: media>

The file exists allright..
[root@localhost /]# ls -l /mnt/dvd/Fedora/RPMS/kdebase-3.5.4-12.fc6.i386.rpm 
-rw-r--r-- 37 root root 29712670 Oct  5 21:28 /mnt/dvd/Fedora/RPMS/kdebase-3.5.4-12.fc6.i386.rpm

pirut suffers the same error message