[OS X TeX] Curious xelatex font problem

[Reinaert Albrecht]

I have a curious xelatex font problem. I'm using mactex (tested both 2007 and 
2008 version) and when I use a user font with fontspec xelatex complains about 
tfm-files not being found but only when run from the command line. When I 
compile the exact same file with texshop everything works fine. 

Using system fonts gives me no problem at all curiously.

Moving the user installed fonts to the system directory changes nothing. As 
far as I can check both the command line and texshop use the exact same binary 
of xelatex. The environment is also the same. I checked this in the 2007 and 
2008 version of mactex and both give me the same problem.

Does anybody have an idea of what is going on here?

Kind regards,

Reinaert Albrecht