Wordsmith99 almost has it...
To intercept the #N/A result, you must use:
=IF(ISNA(whatever)," ",whatever)
this will return a space in place of #N/A...
I should like to have returned a null "", but Y!A then truncates my formula!
The ISERROR() function will intercept more exceptional results:
Function... Returns TRUE if
ISBLANK Value refers to an empty cell.
ISERR Value refers to any error value except #N/A.
ISERROR Value refers to any error value (#N/A, #VALUE!, #REF!, #DIV/0!, #NUM!, #NAME?, or #NULL!).
ISLOGICAL Value refers to a logical value.
ISNA Value refers to the #N/A (value not available) error value.
ISNONTEXT Value refers to any item that is not text. (Note that this function returns TRUE if value refers to a blank cell.)
ISNUMBER Value refers to a number.
ISREF Value refers to a reference.
ISTEXT Value refers to text.