I assume that [Factory Country] is a cyclic grouping. Its hard to diagnose this problem without a sample qvw file that illustrates the problem with your data. Is it possible that one or more fields from the cyclic are not associated in any way with the [Avg. Tot Capacity Per Week] metric?
Although the syntax of your expression looks OK, you could simplify it slightly by removing redundant parts of the expression:
=Dual(GetCurrentField([Factory Country]) & ' (' & num(sum( [Avg. Tot Capacity Per Week]), '#,##0') & ')', sum( [Avg. Tot Capacity Per Week]))
try this expression:
Num(sum(YourValue/Field), '#,##0') &
Repeat (chr(13) & chr(10), rank(sum(YourValue/Field))-6),
figure 6 does mean that 6 is a Rank, the function repeat doesnt kick you in until get to the seventh ranked value in the dimension.