You may be unable to see the button click events firing on certain machines though it may work in some other machines.
Mostly when you are developing in your local system, the events do work well. But once you move the code to production, the button click events may not fire at all.
This might rise after you install the Microsoft .NET Framework Service Pack 1, which will stop the PostBack Events on client side validation.
To resolve this issue, the aspnet_client folder needs to be reinstalled. To do that type the following from command prompt:-
This should resolve the issue.
The above command applies to .NET Framework version 1.1. For 1.0, you need to change the version to v1.0.3705 in the above command.