Substitution in a file dont work with an Array in filename

Hi.

I�ve a script that should substitude the 8th line in a file called xxx.num6.

The "xxx" is set by an array filled with this command:

 
j=0
for Par in *.sys ; do
   Par=`echo $Par | sed 's/\(.*\).sys/\1/'` ;
   Par2[$j]="$Par" ; echo "${Par2[$j]}"
   j=$((j + 1));
done

Now i try to implement the substitution with:

j=0
for dummy in *.sys ; do
   sed '8d' ${Par2[$j]}.num6 > run1.ksh
   sed -e '/ntout/i\tend='$tend_Mges'' run1.ksh > ${Par2[$j]}.num6
   j=$((j + 1))
done

So the substitution works, if i set the Name of the file (e.g. abc.num6) instead of the parameter.
But if I type in "echo ${Par2[$j]}.num6" , the output of the variable is the correct Name. (e.g. abc.num6)

So i think the problem hides into the Syntax of the parameter "${Par2[$j]}.num6" ???