datefilter ad posting date

hi sir,

i ask that one thing when i generate the report Cash Book and Bank Book then one problem is arises.

Posting date filter not working properly in both report .when i filter in 01/01/10 to 08/05/10 (Standard Database)then some data are display in 2008 and 2009 year what the reason. please tell urgentlly.

Thanks

Sunil Mishra