Question marks just started appearing in PDF files created from HTML using ABCpdf

I have a web based application (ASP.NET 2.0) on a virtual dedicated Windows Server 2003 SP2 box, that converts HTML forms and converts them to PDF using ABCpdf. It has been around for years, and hasn't been changed for at least the last two of those years.

Three days ago it started placing question marks throughout the outputed PDF documents.

The question marks seem to correspond with empty span tags in the HTML. Any ideas on why this might be happening, or what I might need to do to resolve it?

UPDATE ------------

The html is generated via xsl and immediately used to generate a pdf.

I did, in fact, have the character   in the positions where the question mark was appearing. However, since this is a way of encoding a non-blanking space, all I could see in the html was a blank space (even when turning on see all symbols in notepad++).

When I replace the   instances in the xsl code with a simple space character, the question marks went away.

Note: I was also able to make the question marks disappear from the final pdf by using charset="iso-2022-jp" However, the intermediate html showed Japanese cha开发者_JS百科racters.

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ABCpdf uses the IE engine from the machine to load and render the html. Have you updated the IE browser version on the machine? For sure it's something related to the IE browser (since you say you made no changes to your xsl / html).

Thanks, Flores