I have IE5.5,SP2, and can't open a pdf document within it. When I reverted to IE5.0 it worked fine, but not in 5.5. Is this related to the info in DomPedro's link, having to do with version 5.5 no longer treating Adobe Acrobat reader as a plug-in? The link says that the problem is caused by the URI not ending in "pdf". DomPedro's link says that a netrwork administrators can resolve the problem by configuring their web server to send a content-type header (MIME type) of "application/pdf" for .pdf files. BUT...IE5.5 worked OK with my pdf files for a while, and now it doesn't. So....does anyone have a solution to this???? Someone from Microsoft, someone from Adobe??