In Excel 2007 use the IFERROR
IFERROR(A1+b1,"You have an error")
in Excel 2003 IFERROR is not available, but you can use ISERROR
IF(ISERROR(A1+B1),"You have an error",A1+B1)
If you really want to get specific and only trigger on #VALUE and not all
errors check out the ERROR.TYPE function in help
