What version OS are you running on your machine, 32 bit or 64 bit. If you are running a 64 bit OS without realizing it, or with realization, you may not be aware that you would require drivers for that 64 bit OS. I suggest you perform a search for that driver the error keeps mentioning on Google. You can also go to the program manufacturers website and see if you downloaded the correct version for your OS. A 32 bit OS cannot run a 64 bit program or driver, but a 64 bit *can* run most 32 bit applications, but cannot run a 16 bit application. The 16 bit applications are not obsolete on the newest and more powerful 64 bit software.
We once all ran 16 bit OSes. When the 32 bit came out most jumped on it quickly because it was so much more powerful and could do so much more, and also run more physical RAM. Now, this is true with the newest 64 bit, in the power and physical RAM capabilities, but because the average user really doesn't need all that extra power provided by a 64 bit OS, most of us are waiting until we have to upgrade. Most motherboards are now support 64 bit OSes, but also support 32 bit.
Another huge issue which stops users from the transition is the fact of drivers needed to run our current hardware. Manufacturers are simply not developing the necessary drivers we must have to run our hardware. So, usually it is only those who really need or require that extra power who are running 64 bit. Gamers run them if they want to actually win games, and other serious professional who must use CAD or other high resource hogging applications. One of these would be architects who create 3D plans, or those who create a lot of animation and special effects such as movie producers. These are just a few of the professional needs for a 64 bit machine.
http://forum.driverpacks.net/viewtopic.php?id=299
http://www.dll-files-download.com/P/2008-01-13/13713.html
Those two links should get you started. All I did was type portcls.sys into the Google search box and hit Enter. If these do not suffice, here is my search results page:
http://www.google.com/search?q=portcls.sys&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
Hope this helps resolve your issue, good luck and have a nice evening.
Oh, and don't forget to first do a search at the manufacturers website for that application and make sure you have the correct version for your system. You can find out what OS version you have on the System Info page, simply hold down the Windows Logo key and then tap the Pause/Break key. The information on your current OS version is on that dialog box (XP) or page, (Vista).