>First the expression is wrong. You must put the whole expression as a char string :

.DynamicBackColor = "IIF(Empty(myTable.Field1), rgb(0,0,0), rgb(192,192,255))"

An additional note- the Dynamic properties often don't take kindly to the RGB function in the expression, and it is often more dependable to just put the color constant as returned by RGB, rather than the RGB function. Also- try to keep all spaces out of the poperty. There is a bug in the Dynamic properties that often causes the properties to be ignored if spaces are embedded in the expression.