the acrobat reader that is running cannot be used to view PDF files in a browser

It appears reader v9 is an incomplete program. It will not operate as it's supposed to. Adobe does not offer support for it other than this un-moderated forum. We are left to figure it out ourselves. After reading many threads on this problem and not finding a solution at the home page for adobe, I've gone with the popular consensus and uninstalled v9 and reinstalled v8.1.2, which now displays pdf documents in my browser as it did before.
Adobe is partnered with MS and is following their lead by only offering paid support. They produce half baked products that don't work and then ignore any requests for help unless you show them the money. They are as arrogant and ignorant as their master.

Having the same issue here; using Windows XP; IE7 and Adobe Reader v9

'The Adobe Acrobat/Reader that is running can not be used to view PDF files in a Web Browser. Adobe Acrobat/Reader version 8 or 9 is required. Please exit and try again.'

De-installed and reinstalled but it still continues giving the same error at each online PDF i want to open.

This is -obviously- a rather no-go stopper for me: whats the use of a pdf reader which cannot read online pdfs ..

HBE