This is what worked for me. I had the same problem, acrobat reader was crashing as soon as it opened a document launched from a diferent application. I tried reinstalling and in the process I noticed that I was reinstalling to the same location - an inbuilt card rather than the main memory. I reinstalled to the main memory and that solved the problem. Now it doesn't crash.
I hope it helps!
I have all of the same issue on a Windows Mobile 6.1 device. I tried installing Adobe Reader into my main memory, but the is not sufficient space. I have all of my programs installe on the storage card. I don't know what to try next.