I need help for shell script

Question

I need help for shell script, this script on my pc works ubuntu 14.10 but on samba server machine ubuntu 14.04 is show me error: tar you may not specify more than one -acdtrux' option --delete or test-label.... Please help. Script is for archive files older to 10 days. There is script:

#!/bin/sh

# What to backup. 
backup_files="/usr/*"

# Where to backup to.
dest="/home/milan/Desktop"

# Create archive filename.
day=$(date +%F)
hostname=$(hostname -s)
archive_file="$hostname-$day.tgz"

# Print start status message.
echo "Backing up $backup_files to $dest/$archive_file"
date
echo

# Backup the files using tar.
files=$(find $backup_files -type f -mtime -10)
sudo -s tar cf $dest/$archive_file $files

#files=($(find /usr -mtime -7))
#tar cvfz $dest/$archive_file.tar.gz "${files[@]}"

# Print end status message.
echo
echo "Backup finished"
date

# Long listing of files in $dest to check file sizes.
ls -lh $dest