Load MMdriver application not working

Hello,

I have dell 14z 5423 bought few months back.

recently i switched to windows 8.1 from my previous operating system. After I installed the driver for AMD graphics( downloaded from the dell site for my service tag) a message "load mmdriver application  not working" appears after about a minute of booting my laptop.I feel that my AMD graphics is not working properly. Also, for a program Autocad 2014, when I set it to high performance in the switchable graphics option by catalyst graphics manager it doesn't runs but if i set it to power saving then the program works.But for some other small programs they run when i set them to either high performance mode or power saving mode.

What is the problem?Is the AMD graphics being used or is being useless? Why does load mmdriver application  not working  appears? how can i solve it? and how can i make autocad 2014 make use of the AMD graphics instead of the inbuilt intel graphics? Please help...

Thanks