Just a few basic to help make sense for you.
When you want to install a program or App etc they come in various ways.
A file with an extension
.cab can be installed directly on your Ax
.exe needs to run on the PC and installed to the Ax using Active Sync.
.zip needs to be unzipped and the file inside installed in the appropriate way. (.cab or .exe)
In reality, all the .exe does is create a .cab file on your PC then move it to your Ax so that it can run there.
The .cab is the real program file.
A .cab can be placed anywhere on your Ax (main memory, SD or CF) and run from there.
After the program has been installed the .cab file can be deleted.
It's well worth keeping the .cab files of programs that you use on a separate SD card so that if you have to do a hard reset you can reinstall your programs on the go. Also make a note of all your registration codes etc. You probably don't have any yet.
Active sync is a very slow way of transferring data to your cards. The Ax is USB 1 and Active Sync chokes it even further.
If you want to put big movie files on your cards, best to buy a card reader, it will go much much faster.
As for the SDHC driver, you only need it if you have an SDHC card and it will apparently only read up to 4gig of the card.
You can buy 4gig SD cards, so unless you have another device that needs the SDHC, you may as well stick with simple SD.
But if you want to install it.
Following my info above.
Go to
this thread.
Download the SDHC.zip file that is attached to the first post.
Unzip it on your PC.
From memory, it contains a .cab file.
Move that .cab file to anywhere on your Ax. (via explore in active sync or written straight to a card)
Go to the file on the Ax in file explorer and tap on it.
It will then install the driver.
Soft reset your Ax.
If I'm wrong and it's an .exe file in the zip, run it on your PC as you did with TCPMP.
I hope this diatribe makes sense.