Failed to fetch updates

[elk dolk]

Hi All,

I try to update my Linux Box (Ubuntu 10.10) but I get the following message:

Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/l/linux/linux-libc-dev_2.6.35-1027.48_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/k/krb5/libk5crypto3_1.8.1+dfsg-5ubuntu0.4_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/k/krb5/libgssapi-krb5-2_1.8.1+dfsg-5ubuntu0.4_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/k/krb5/libkrb5-3_1.8.1+dfsg-5ubuntu0.4_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/k/krb5/libkrb5support0_1.8.1+dfsg-5ubuntu0.4_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/l/linux-meta/linux-generic_2.6.35.27.35_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/l/linux-meta/linux-image-generic_2.6.35.27.35_i386.deb
 404  Not Found [IP: 91.189.92.166 80]
Failed to fetch 
http://security.ubuntu.com/ubuntu/pool/main/l/linux-meta/linux-headers-generic_2.6.35.27.35_i386.deb
 404  Not Found [IP: 91.189.92.166 80]

why is that so?

regards