Hi hld,
I read this several hours ago, and had started a reply. That there have been no responses in close to 19 hours likely indicates others have had as much trouble decoding what you are saying as I have had.
So far, I think that you have two Tables, that the tables are on separate sheets in the same document, that you are having some difficulty with a cell reference in one of those tables to a cell in the other table, and that the difficulty is connected with sorting one of the tables.
You mention a cell address ("worksheet(1);cell A;2)
which has little or no similarity to a legitimate cell reference in Numbers.
The use of the semi colon ( ; ) in that reference does suggest you are in a region where a number having a decimal part, such as a currency amount, would be written "€2,35" rather than one where (with a different unit) it would be written "$1.25". Please confirm, if that is the case, as it does make a difference in the notation of formulas.
Please take the time to rewrite your description of the issue. Screen shots showing the tables, the formula making the reference (as it appears in the Formula Editor of in the box below the document window), and a second showing the same formula after the sort of the table containing the referenced cell might be useful to understanding the question and determining a solution.
Regards,
Barry