Enter Parameter Value Prompt in Reports

[rjr]

When I build an expression using the syntax: =[table name]![field name]/[table name]![field name], I get the prompt "Enter parameter value" when I run the report. If I remove [table name}, I don't get the prompt. The syntax is from using the Expression Builder feature in the Control Source of the Properties of a text box I use for the expression.

I am simply asking for Price/square feet. Why do I get the prompt? Why does use of the table name in the expression cause this. Please advise.

Rick