Thanks CC. You are correct. The failing workstations (turns out there are more than one) are running with Excel 97. Replace$ is not supported under this version.
The .xls was created with Excel 2002.
I am using Replace$ in some VBA code in Excel without any problem. I have distributed the file to several testers and for the most part it's ok.
However, one user is getting "Sub or Function not defined" and the Replace$ function is highlighted.
Does anyone know why this is happening?