PROBLEMS WITH COUNTIF

Ihave aworkbook with 3 sheets, one a list of names/adresses in our database andsent to a company to check the addreseses for validity(my 1st sheet) and sent to the USPS (my 2nd sheet. to print bar-coded address labels.(my 3rd sheet) for some reason a label is not produced for a few names in the list sent to the USPS. I"m trying to determine why.Also when I try to modify my countif function in a different column I get a VALUE! error saying the work book is not open,but, of course, it is simply a sheet in th same workbook