Is your Adobe Reader 7 plug-in for Firefox not loading pdf files as expected? If you are getting a blank white page instead of the Adobe Reader launching and displaying the pdf file you wanted to see (by clicking on a link to it), this “solution” might help:
Uninstall all Adobe Reader software from your machine (Control Panel > Add or Remove Programs) and remove all the various versions of Adobe Reader and the updates. There were 5 or 6 different programs to uninstall from my machine, from Reader 6 to Reader 7 with all the updates in between.
Restart your machine.
Then download and install the latest version of Adobe Reader. That worked for me…