[Lucky9teen]

Try a couple of things:

Open Adobe Reader
Open the Edit menu and select Preferences.
On the left hand side of the preferences window, select the Internet category.
Make sure to uncheck the “Display PDF in browser” option.

OR:

http://helpx.adobe.com/acrobat/kb/runtime-error-roaming-profile-workflows.html

http://support.microsoft.com/kb/822521

[knittnmom]

If that doesn't work, this is what fixes that sort of error for some of our users:

Open Adobe Reader

Click on Edit, then on Preferences

From the Categories on the left side, choose General

Uncheck "Enable Protected Mode at Startup"

[LaserJock]

I'm no techie, but I started having similar trouble opening PDFs after using a government online form that required me to change some of the settings on my browser. I don't recall if I simply went back and undid those settings or whether I clicked the option to restore Explorer to its initial installation settings, but that fixed me up.

[annieokie]

That worked for me with a cavaet: Now IE has a warning box on top: To protect your Security, internet explorer blocked this site from downloading files to your computer, click for options........X

BUT, I can live with that.

THANKS, your a great help. Now I will go look at your links.