We had similar problems with both the upgrade to 9.4.2 and 10.0.1. We would either get the download/save screen or a black screen would appear and eventually error out and freeze up the machine when we tried to hit pages that loaded pdfs stored in Oracle. We found the pdfs would load when using Chrome or Firefox.
We're running winXP SP3 and mainly have users using IE 7 and IE 8. We were eventually able to solve the problem by doing the following:
Now we have users who can successfully load the pdfs from Oracle who are running either 9.4.2 or 10.0.1.
Hope this helps!