Problem with firefox on xp with css

Hello Friends,

can someone help me about this??? I have tyried to create a navigation bar... visit at : http://goo.gl/Ef3tZ

i have check it out on chrome, firefox 15 & it was looking good to me in windows 7

my client complaint about the last navigation item... sejours linguistiques... is dropping onto a second line.. my client is using firefox 15 & xp.

is there any one seeing the problem?? could it be the problem regarding the fact that she is running xp?

if there are some problem, kindly guide me about this.

looking for help...
Thanks in advanced!

Not sure if you've changed anything since posting, but I'm on XP with Firefox 15 and there's no problem here. It's possible she's set a zoom or text setting that's making it wrap.