Error about Unsupported file type or damaged file in Acrobat X or Reader X

When Acrobat X or Reader X try to open a PDF, it fails to open and the following error appears:

<product name> could not open "<filename>" because it is either not a supported file type or because the file has been damaged.

Solution

The file is a malformed PDF. Create a PDF file that conforms to the PDF standard.

Additional Information

Acrobat X products can strictly enforce adherence to certain aspects of the ISO PDF file format standard for security reasons. Since it is possible to use malformed PDF files as an exploitation vector, nonstandard constructs aren't permitted.