link to pdx from pdf, but no launch when using Reader

We have a collection of pdf documents and have built a search index for the collection. The pdf and pdx files can each be opened by Reader via desktop icons.

We have also built a "table of contents" pdf which is a single page in two columns showing a list of the books in the collection. Each item listed is linked to the corresponding pdf. We can open the TOC with Reader and jump to the books through these links.

We also place a link to the collection search index on this TOC page. Unfortunately, Reader will not launch the index through this link (saying there is no file association found for type pdx). Since Reader opens the pdx when clicking on its icon, we think the file association remark is spurious, but what can we do to enable Reader to launch the pdx from this link?

Note that when a machine has Acrobat Standard or Acrobat Pro installed, all links work. The problematic case has been on machines where only Reader is installed, and not Acrobat Standard or Pro. For distribution purposes, we need to ensure that sites where only Reader is available can use the search index from the TOC page.

We're doing all this on XP boxes.

Thanks for any help.

-rw