I very afraid I'm about to enter the Bermuda Triangle between three vendors - Wacom, Adobe and Microsoft - so please be kind ....
I have a brand new Windows 7 64-bit machine. I downloaded the latest driver for my Wacom CTE640 drawing tablet and hooked it up. Works great.
Later, I opened a document with Adobe Reader and it opened up a dialog indicating it needed to set up preferences in Reader as this is the first time I was opening it using Windows Assistive Technology (or words to that effect). Now this is only documents that were rendered electronically (a PDF Printer in my case).
Even if I set things up, every time I open this type of document, I get a progress-bar dialog that indicates the document is being scanned.
So somewhere between Microsoft, Adobe and Wacom there is something about the installation of this driver that is making the latest release of Adobe Reader think that I've activated Assistive Technology.
If I uninstall the driver, Adobe 9 goes back to its normal behavior (just opens the document and lets me read it).
I'm being careful not to point my finger at any one vendor here; I understand that this could be an issue with the driver somehow registering something with the OS that makes the OS think it is an Assistive device, it could be something in the OS that is misreading what this device is or it could be Reader 9 misinterpreting something.
I hope someone from Adobe reads this and investigates.