NIS09 add on package intall problem

When I try to install NIS09 add on package, the following message shows up:
"Another installer is currently running. Please wait for it to complete and try again."
I spend more than 4 hours whith several "technician" guys from overseas (India) trying to solve the problem, they unistall/install NIS for about 3 or more times, checked running process, starup programs, services, even one of them went into the Registry.......nothing solved the problem.
I'm going crazy now, for me it is very important to have this package since i have childrens at home. Please help me.

(My sytem: Brand new DELL Studio laptop, Windows Vista Home P.)