Sounds like it's not embedding the font in the PDF and substituting the font - where "n" would be a bullet in the font - when substituted to another font it would be just an "n".
I actually can't find this font in the Helevetica suite, which makes me think it was a free font or something that was created to match the Helvetica fonts - but it lacks proper encoding information for embedding in a PDF.
Do you have the license to check if embedding is permitted?
If it's not I suggest finding an identical bullet from a font that does allow embedding.
I used Acrobat 1.4 converter.
I use Indesign CS5
Do you mean you use the Distiller? If so, is there a good reason not to use the standard PDF Export from within InDesign?
Is this an automatic bullet, or a typed bullet? If it's type, select it and check to see waht font is really applied to it. If it's automatic, go to the dialog to find out. It does sound like a font not embedding.
It is a typed bullet. The weird thing is that i can't recreate the problem.
It is made from default indesign exporter.
Try exporting to PDF with a higher version of Acrobat compatibility.
The "n" indicates that the bullet originally is formatted with "Zapf Dingbats".
If you change the font formatting away from "Zapf Dingbats" it is represented simply as an "n".