I have following formulas in a worksheet, they work perfectly and provide the
exact results I'm looking for. However, when another person opens this file
on their PC, whether from the same network directory or from an e-mail
attachment, all the results from these formulas turn to #NAME?.

Need to find out why this happens and how to correct this issue.

cell B1 and C1 are the first and last name of an employee.
cell D1 is the employee's birthdate.

cell P1 has the following formula and the result should be the hire date
found in a table that is in a separate TAB in the same file:

VLOOKUP(B1&+","&+C1,'Hire Dates'!$B$2:$C$949,2)

cell Q1 has the following formula and the result should be the years and
months employed:

IF(P1="","",TEXT(TRUNC(YEARFRAC(D1,TODAY()),0),0)& +IF(TEXT(TRUNC(YEARFRAC(D1,TODAY()),0),0)=1,"
yr., "," yrs.,
")&+TEXT(TRUNC((YEARFRAC(D1,TODAY())-TRUNC(YEARFRAC(D1,TODAY()),0))*12,0),0)&+IF(TEXT(T RUNC((YEARFRAC(D1,TODAY())-TRUNC(YEARFRAC(D1,TODAY()),0))*12,0),0)=1," mo. "," mos."))

cell R1 has the following formulas and the results should be the years and
months of the person's age:

IF(P1="","",TEXT(TRUNC(YEARFRAC(D1,TODAY()),0),0)& +IF(TEXT(TRUNC(YEARFRAC(D1,TODAY()),0),0)=1,"
yr., "," yrs.,
")&+TEXT(TRUNC((YEARFRAC(D1,TODAY())-TRUNC(YEARFRAC(D1,TODAY()),0))*12,0),0)&+IF(TEXT(T RUNC((YEARFRAC(D1,TODAY())-TRUNC(YEARFRAC(D1,TODAY()),0))*12,0),0)=1," mo. "," mos."))

cell S1 has the following formula and the result should be true or false as
to whether or not the employee has 5 years of service and is 55 years old.

IF(P48="","",AND(TRUNC(YEARFRAC(P48,TODAY()),0)5, TRUNC(YEARFRAC(D48,TODAY()),0)=55))