Cognos 8 Report Studio Unionset Error

[shatten]

Hi all,

I have a report which on a single crosstab combines calculations for two measures and two dimensions, just to illustrate, there is a measure for amount actual and an amount  budget, the dimensions are current and last year. There is also a graph linked to the same query.

All I wish to do is to say when either of the two amounts is 0 filter it out.

However, when I try to use a detail filter to achieve this I get the following error:

"The "unionSet" operator is only applicable on sets with the same dimensions. The number of dimensions in two or more sets is different."

Has anyone encountered this error? Can you please provide me with any pointers as to where to look?
Even more weird is that when I remove the graph, which obviously I do not wish to do so, the filter works.

Thanks in advance,
ShatTen