Hi Bob, 

I'm curious whether you actually need the nested loop and why you need the zcnt. 

In my opinion this should work for you:

for zql in InvItems[Article.itemCatg = 1 and WSfix = null] do
InvItems.(WSfix := Article.WScur);
end;
for Zql in InvItems[Article.itemCatg = 1 and RETLfix = null] do
        InvItems.(RETLfix := Article.RETLcur)
    end;

What you did right now was

per item you wanted you have updated invitems.retlfix several times
so you had a loop which did

2 changes if you had 1 invitem.
1+2+1+2=6 changes if you have 2 invitems
1+3+1+3+1+3=12 changes if you have 3 invitems

That's why ninox crashed with 200 items.
If you remove this nested loop then it will be a lot faster.
if you write "do as transaction" before the loops - it will become even faster :-)

I am with Peter , do you need to put the 2nd loop inside the first one?

Also, I may be wrong, but I think you need to change:

do as server
for Zql in InvItems[Article.itemCatg = 1 and WSfix = null] do
    Zql.(WSfix := Article.WScur);
end;
for Zql in InvItems[Article.itemCatg = 1 and RETLfix = null] do
    Zql.(RETLfix := Article.RETLcur)
end;
end

Lines 3 and 6, remove the reference InvItems and put in the loop variable. Why? Well if you leave InvItems then you are modifying all related records in InvItems. What if you had records in InvItems that all ready have data, then now you will over write the fixed. By switching to the loop variable you are only touching the record that matches your filter criteria.

Or you can try:

do as server
for Zql in InvItems[Article.itemCatg = 1 and WSfix = null or RETLfix = null] do
    Zql.(
        if WSfix = null then WSfix := Article.WScur end;
        if RETLfix = null then RETLfix := Article.RETLcur end
    );
end;
end

Line 2, filters for all InvItem record with Article.itemCatg = 1 and either WSfix = null or RETLfix = null. 

Lines 4 and 5, should only copy data when the fields are empty.

Another way you can simplify:

do as server
    InvItems.(
        if WSfix = null then WSfix := Article.WScur end;
        if RETLfix = null then RETLfix := Article.RETcur end;
    )
end

With the power of relationships, this tells Ninox to just go through all related records and do whatever you want.

Though you can probably skip the do as server as this should be pretty fast even with 200 records.