I am having the same problem. I am using OSX 10.6.8 and safari 5.1.7 and can not view downloaded PDF files from the internet. Anyone know how to fix that? It really should have been done a while ago, this has been going on since January of this year.
I am experiencing the same issue, however, there are no Adobe plug-ins. Safari should support PDF viewing. Current workaround is to right-click on blank PDF window in Safari > Select Open PDF in Preview. Lame but it works for now
I'm having this problem as well - but not clear as to where to find these internet plug-in folders - I did a search for them in File Folder but haven't located! Thanks in advance for your help as this will definitely make my day(s) to come!