Microsoft Excel 97 claims three new global constants: Checked, Grey, and Unchecked. If you used one of these now-reserved words as a control name, you will get an error. Note that in Microsoft Excel 95, the following code would work for a checkbox named "Checked," while in Microsoft Excel 97, it does not:
[Checked].Value = xlOff
The best way to work around this issue and to avoid similar issues is to use a naming convention for all variables. Typically, a variable-naming convention uses a prefix that identifies the variable type concatenated to the variable name. For example, an option button formerly named "Checked" could be named "optChecked" (although it should be noted that while Boolean variables are traditionally named as adjectives, to avoid confusion, objects are not).