Hi,
PDF file almost always use subset font to save file size. For example, Arial font covers thousands of characters. However if you only have a PDF file with "Hello" in it using this font, then only font data for those five characters are saved in your PDF file. In this case font data for the thousands of characters that are not used in your PDF file would not be saved in your PDF file. This is the purpose of subset so it is perfectly normal to use font subset.
You can try to open the PDF file with Adobe PDF reader and see if it can display the text. If it also complains about the problem, then there must be something wrong more than font subset (or somehow the subset data we generated is wrong). In that case you can send a sample input file and sample code to us so that we can reproduce the problem here. Once we have that we will look into it and see what we can find. See here for more instructions on how to submit test project to us:
http://www.essentialobjects.com/forum/test_project.aspxThanks!