Slackware :: Restoring Whole System From A Tar.gz?

I save my whole system to a .tar.gz file weekly except for the /proc content. I have used this backup a few times to restore my system without issue.

Last time I restored, I discovered the following 2 issues I home somebody can explain:

#1: while extracting the .tar.gz using tar xzvf filename.tar.gz, I get the following error near the end of the restore process "tar: Incorrect Length". This error only occurs when I boot the system with the slackware 12.1 disc 1 CD. It does not occur if I try to restore from my working system, same file. Other than this, everything seems to be restored properly and the system boots up properly. I am just concerned by the meaning of this error.

#2: After restore, I do lilo -C /mnt/etc/lilo.conf to make sure the systems boots up properly. This works... however, I have discovered that just this won't make module autoloading work after the restore. When booting the restored system, no module autoload !

I have correct this by just entering setup when booted up using the slackware 12.1 disk 1 CD and going thru addswap, set target without format and the going thru the configuration menu and cancelling all question.

Why would modules not load automatically ?