Acrobat 8 adds extra characters to the running header

I'm using Acrobat 8 Standard on an XP machine with Office 2003. My documents use running headers and footers. Both headers and footers derive their content from the document properties or the heading level. When I create a PDF using Acrobat 8, it's adding extra characters to the running headers. For example:

0BContents
8BSystem Requirements

Updating the field doesn't help. Does anyone have any ideas?