Server :: Unable To Decompress TGZ Backup File

I have recently upgraded to Bugzilla3 and I wanted to restore my bugzilla database with my backup but when I attempt to tar -xvvzf file.tgz I get the error:
gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error exit delayed from previous errors

My script that creates the backup is:
#!/bin/sh
datestr=`date +%m-%d-%Y`
bakdirpart="bugzilla.backup.$datestr"
bakdir="$HOME/$bakdirpart"
mkdir "$bakdir"

(cd /etc; tar cvzf $bakdir/mysql.conf.tgz mysql)
(cd /etc; tar cvzf $bakdir/apache2.conf.tgz apache2)
(cd /usr/share; tar cvzf $bakdir/bzreport.share.tgz bzreport)
(cd /usr/share; tar cvzf $bakdir/bugzilla.share.tgz bugzilla)
(cd /var/lib; tar cvzf $bakdir/mysql.hotdb.tgz mysql)
(cd /var; tar cvzf $bakdir/www.tgz www)
(cd "$HOME"; tar cvf "${bakdir}.tar" "$bakdirpart")

Is there any way to recover my backup copy?