Date does not change in tally 7.2

Dear Friends,

       I have a problem with Tally 7.2.... I have got tally 7.2 data of one of our clients for accounts preperation.... But when I try to change date invoucher entries, it doesnt change... I called the client and asked them to change date in their system and it changed... This happens only with our office software and for this client only... I tried to chage date in other clients data in tally 7.2 and it is changing.. Kindly help me out to fix this problem....