Tar - Error Exit Delayed From Previous?

I have a tar.gz file when i issue command like this to untar,

mysql@test ~]$ tar xfvz mysql-advanced-5.5.17-linux2.6-x86_64.tar.gz

output:

mysql-advanced-5.5.17-linux2.6-x86_64/bin/mysql2mysql
mysql-advanced-5.5.17-linux2.6-x86_64/bin/mysqlslap
tar: skipping to next header
tar: Archive contains obsolescent base-64 headers incomplete literal tree
gzip: stdin: invalid compressed data--format violated
tar: Child returned status 1
tar: Error exit delayed from previous errors

But when i check i found the file like below,

mysql@test ~]$ ls
mysql-advanced-5.5.17-linux2.6-x86_64

This means its completly untar the file?Why that error is showing?