I can work without them but Im not sure that they are the problem.
If can - do it! And see - do you have the problem or not!
Insert in the Mathcad sheet not a reference but the second sheet itself (in collapsed area). Ans check errors!
have you fulfilled the following rules?
furthermore there must be no redefinition of functions, variables and constants in each worksheet.
Create daily copies of the main worksheet and possibly of the other files as well.