Excel2003 ... Weeknum vs Conditional Formatting???

Cell E1 ... =IF(ISBLANK($D1),"",D1+7) ... Return = 01/14/07 ... ok
Cell E3 ... Conditional Format Formula ... Format Pattern Gold ... not
working???

=weeknum(today(),2)<weeknum(e$1,2) ... Returns error message =

"You may not use references to other worksheets or workbooks for Conditional
Formatting criteria."

I am stuck ... Help! ... Thanks ... Kha