rocknbil - 6:06 pm on Dec 22, 2010 (gmt 0)
Welcome aboard MelanieGLS!
Been a long time since I worked with DTP so the technology probably has changed. Jumbled text of any kind is indicative of a corrupted font file, or that it's sending the fonts as embedded and not really outlining them as it should.
The first stop is to see if your exported "outline" file exhibits these problems prior to sending. You really need a PostScript printer to do this, but you can print separations from some application, depending on what you have. One scenario is export the PDF, then open it in directly in InDesign or Photoshop and print to any printer as separations. (The scenario below may render this as an ineffective test; since the fonts are installed on your computer, you may not see the problem.)
The other possibility is the font type you are using for this font: Type I, II, III, or Truetype? If you're on a Mac, there are (used to be) legacy nondescript (i.e., no one knows what's wrong but it's still broken) problems with TT fonts exported to PostScript.
What is the brand and model of the imagesetter? This is (often) important. Do you have the imagesetter's PPD installed on your computer? That may help; install this imagesetter's PPD/profile and select it as the Postscript printer when making the PDF. You can get the PPD from the publisher. (PPD=Postscript Printer Description)
You can also *try* exporting the file from InDesign as an EPS with the text as outlines (if it has that functionality, it should), then import that to PDF.