I am trying to make a design table for an assembly.  I have everything dimensioned.  I created a design table the way it says in the tutorial and added all of my parameters.  I then tried to create functions and relationships within the table based on the differences between actual design and the way sales will call out dimensions.  In order to do this I inserted several columns before the parameters where sales could type their numbers and where the parameters were I added equations linked to the sales numbers.  For some reason I keep getting errors.  One error was regarding the heading not being a valid name.  I tried all different names, nothing seemed to work.  I deleted the name and it still won't create the instance.  What do I do?