Thousand separator comma missing

[BlowingWind]

1. I am on ubuntu 14.04.  Testing upgrade to IPB 4.1.4.1 from 3.4.6

2. The numbers of Total Post, Total Members on my forum is shown as 123456 (IPB 4.1.4.1) instead of 123,456 (IPB 3.4.6) 
Note the missing comma 

3. What to do to get back the comma. 

Thanks.