Adobe InDesign CS2 serial number invalid

I install the programm successfully and when I open it the window appears my name and organization and i completed except that my serial number is invalid the serial number printed on the cd pack was I used to install and it has no problem until I open the program. When I re-enter the said serial number, it response like this, "The serial number you provided is not valid. Please check your serial number and re-enter it." I follow the instructions but yet still the same response. What I'm going to do that it is not my fault.

Please help me, it is badly needed!!!!