I think I found the reason for the problem. Because the font you use seems to be very similar to Times, I didn't see that the pages in EPUBReader look different than the one directly in FF
It is probably caused by this statement in EPUBReader's css-file:
"font-family: parent !important;"
This statement is used for "body, div, span, p". The css is applied to the pages of the epub-file. I've added this line because the users should be able to change the font of the epub. If the users want to have "arial", "parent" is replaced by "arial" and everything works fine.
"parent" is used, when the font defined in the book should be used. Obviously seems "parent" not the right value to reach this goal. Any idea which is the right value?
Sorry for the headache this may have caused