Help with saving an Excel file to .htm

I am trying to save an excel file to a .htm file but I could get it to save for me. Manually, I can do it but AppleScript seem to error out at the Save function. Below is what I have written:
tell application “Microsoft Excel”
Activate
Save ActiveWorkbook In “Umpire of RE:Users:do:Desktop:Sheet1.htm” As «constant &wff#htm» given «class
end tell

Thanks