If you are unable to render Cognos reports as PDFs but they run correctly as HTML, you likely are experiencing a font error.  Check for this error to confirm:

CCLAssertError:0:Fatal: CCL_ASSERT_NAMED(bFoundFont, “[RSPdfOutputText::onDISetText] No font available for the text data”);

Cognos report PDF generation requires that you have:

1. fonts installed on your Cognos server, and
2. the Cognos configuration setting for fonts defined properly so those fonts can be found.

To resolve this, you need to go into Cognos Configuration and modify the settings for the Environment > Font Settings > Physical Font Location.  The fonts included with your Cognos 10 installation should be found in your C10/bin/fonts directory.  To see these fonts, make sure your font setting includes “../bin/fonts”.