Okay, I'll take a stab at it.
You can think of "DRM" as a sort of electronic padlock. Companies put it on their books to keep honest people from "stealing" their books. (
Dishonest folks just pick the lock and go on -- silly, huh?)
As with any lock you need a key to open it, and all the different "brands" of locks have their own unique keys. The first problem you're running into is that the Reader only has the 'key' for Sony's 'lock' and that 'key' can't open the Adobe lock.
There are, as was mentioned above, ways to 'pick' the lock, but it is legally questionable, and it's a good deal more involved than it sounds like you'd want to mess with.
The second thing you would run into, if you got past the lock, is that your Adobe files are most likely formatted to go with a Letter sized 'page,' and the Reader's screen is a bit less than half that size.
Because PDF format is designed specifically to preserve the way text/pictures/whatever is arranged on the page (the layout, if you will), when you put that page on a smaller screen, the text gets too small to read, while the layout is preserved beautifully. The problem is that PDF isn't a good choice for e-books, because an e-book needs to adjust the layout to fit the screen it's on, and PDF is designed specifically
not to do that.
There are some utilities around here that can "cut" the PDF pages into two pieces (top & bottom) so that the text can be read on the Reader's display, but you'd have to pick that lock to even get to the point of being able to run the utilities on the file, and then there's the running the utilities themselves, which might likely be more than you'd want to mess with too (it's not really
difficult, it's just got fair number of steps, is all
).
Unfortunately, the same 'lock' will most likely also prevent you from simply copying the text out of your PDF file into MSWord (or another word processor) and saving it as an RTF file (just another file format that the Reader can read without converting).
I hope that helps clarify what's going on, though I know it's not any help at all getting you to where you want to be.
I can suggest that you browse the
e-book upload section here at MobileRead, the books there have been specifically formatted to work on the Reader without any fuss (just look for "Sony BBeB" in the "Format" column). It's all Public Domain stuff, so you don't have to worry about the legality of it at all (we work pretty hard to keep track of that), but there may be books that interest you there, depending on your interests, of course.