If you want to end a process at a certain time, you can't use Task Manager.
You will need to use Task Scheduler. Start > All Programs > Accessories > System Tools > Task Scheduler.
On the right panel, select Create Basic Task. Give the Task a Name, and click Next.
Select which time you want Vuze to close. Normally you would choose Daily.
Click Next and select the Time etc.
Click Next and select Run a Program. Type in "TASKKILL /F /IM "vuze.exe"
Continue to the end. That's it.
A better option is to use uTorrent which has an inbuilt scheduler, no need for any external scheduler with annoying options.