PXE AVG RESCUE CD - why updates don't work?

Question

System administration

Setting up PXE AVG.
Menu:

LABEL AVG Anti-Virus Scanner
KERNEL images/antivir/avg/isolinux/vmlinuz
APPEND initrd=images/antivir/avg/isolinux/initrd.lzm root=/dev/nfs netboot=nfs nfsroot=192.168.5.1:/pxe/images/antivir/avg ip=dhcp

NFS ball

/pxe/images/antivir *(rw,sync,no_wdelay,insecure_locks,no_root_squash,insecure)

The problem is that the database update is not installed (neither via the Internet, nor from a flash drive), it reaches 40% and the error: Update failed: a .bin fuke is missing.
He downloads the files himself, says that everything is ok. From a flash drive, the usual avg eats the update calmly.
What could be the problem and how to install updates?