Error message: Helvetica Medium outline font missing when creating PDF's. Where can I downlaod it and why is it suddenly happening?
OS? Version of ID?
This means that either you have an extra Helvetica Medium font installed and it's interfering with ID finding the T1 version, or the T1 version is damaged. I found this really old thread that explains it fairly well: http://www.asadesigner.com/22-indesign/2d812de56777cc90.htm
The good news is that it's probably only affecting the page information marks.