Can't execute star cronjob

Hi all,

I wrote a script for backup purpose. If I execute it from shell prompt 
everything is as expected. Script looks like:

/root/tblib.sh

# Exclude direktoriji su navedeni u star liniji sa sintaksom "-V 
pat=subdir/\*"
# Log je u /tmp direktoriju u formatu bck-dd_mm_yyyy-HH:MM:SS.log


# Glavni parametri
BckRoot="/lib" # bez zavrsnog "/"
# /Glavni parametri

#Ostali parametri
Opcije="-fifostats -multivol -time"

MailTo=root
BlockSize=8m
FifoSize=128m
TapeDev="/tmp/arhiva.star"
# /Ostali parametri


PocDir=$PWD
BckScrpt=`basename $0`
BckDateFormat="+%d.%m.%Y-%H:%M:%S"
BckStart=`date $BckDateFormat`
Log="/tmp/tblib-$BckStart.log"
OpisTxt="$BckRoot/BackupInfo.txt"

#cd ${BckRoot}

echo "$PocDir/$BckScrpt" > "$OpisTxt"
echo >> "$OpisTxt"
cat $0 >> "$OpisTxt"


if [ -e $Log ] ; then
    rm "$Log"
fi

cd ${BckRoot}

echo 
"***************************************************************************" 
 > "$Log"
echo "* Backup skripta - $PocDir/$BckScrpt > $Log" >> "$Log"
echo 
"***************************************************************************" 
 >> "$Log"
echo >> "$Log"
echo "Backup START $BckStart" >> "$Log"
echo >> "$Log"


#mt -f /dev/st0 setblk 0
star -c bs="$BlockSize" fs="$FifoSize" $Opcije -V pat=firmware/\* -V 
pat=security/\* f="$TapeDev" . 2>> "$Log"

BckEnd=`date $BckDateFormat`

echo >> "$Log"
echo "Backup END   $BckEnd" >> "$Log"
echo >> "$Log"

cat "$OpisTxt" | mail -s "Backup poceo $BckStart, zavrsio $BckEnd" -a "$Log" 
"$MailTo"

rm "$OpisTxt"
cd ${PocDir}


I wrote rootcrontab file with following contents:

SHELL=/bin/sh
0-59/1 * * * * /root/tblib.sh

So, my cronjob (only for this test purpose) will execute every minute.
Result is mail message with following in attachment:

"
***************************************************************************
* Backup skripta - /root/tblib.sh > /tmp/tblib-03.10.2005-13:33:01.log
***************************************************************************

Backup START 03.10.2005-13:33:01

star: No such device or address. Cannot open '/dev/tty'.

Backup END   03.10.2005-13:33:02
"
If I execute same script from shell promtp I get following attachment:

"
***************************************************************************
* Backup skripta - /root/tblib.sh > /tmp/tblib-03.10.2005-13:28:21.log
***************************************************************************

Backup START 03.10.2005-13:28:21

star: fifo had 5354 puts 8 gets.
star: fifo was 2 times empty and 0 times full.
star: fifo held 44774400 bytes max, size was 134217728 bytes
star: 8 blocks + 0 bytes (total of 67108864 bytes = 65536.00k).
star: Total time 3.162sec (20726 kBytes/sec)

Backup END   03.10.2005-13:28:25
"

Why I am getting this "star: No such device or address. Cannot open 
'/dev/tty'." error?

Zoran