I have been running Mandrake linux on my home PC for about 18 months, and I am very happy with it. The nearly total lack of viruses and other nasties that affect Linux is great, and so is its stability.
Wine is a windows-emulator program for Linux, and it does run many windows programs, but I never could get it to run Autocad cleanly.
Here is one way to run Autocad under Linux (and any other windows software) : Install VMWare Workstation on your Linux Machine.
VMWare lets you set up a virtual machine with a guest operating system. Install windows on this virtual machine, and then install Autocad on it too.
The result is very stable and friendly. Gives you the best of both worlds really.
VMWare Workstation can be downloaded from the VMWare website, with a 30-day free trial. To buy it costs $US189. Well worth a look, IMHO.
Mark M