embedding font in Flex CSS locally with a installed font works, but w/ url to refer to a ttf font file doesn't

Question

I'm trying to embed a font in my project by using url("font.ttf") rather than local("Font Name"), but it doesn't seem to pick it up. The font in question is called "Gotham Bold". When i view the details of the font, the font weight is regular, however when i use local("Gotham Bold") in the css i have to specify fontWeight: bold or else it wont pick it up. But when I use url("folder\Gotham-Bold.ttf"), and specify fontWeight: bold, it says that font weight is not found for that TTF. If i remove the fontweight, there's no errors, but the font is not applied to the text. any ideas please?

Thanks