[R-SIG-Mac] Special characters not plotted

[Ralf Schäfer]

Hello,

I have a problem with the plotting of special characters that just occurred recently.
For example when I use the following code:

plot(1,1)
mtext(expression(phi))

Instead of the special character I get a black square. This actually happens for all special characters in a plot.
Any idea why this occurs? May be even related to fonts on my Mac?

 Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: MacBookPro3,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2,4 GHz
      Number Of Processors: 1
      Total Number Of Cores: 2
      L2 Cache: 4 MB
      Memory: 4 GB
      Bus Speed: 800 MHz
      Boot ROM Version: MBP31.0070.B07

System Version: Mac OS X 10.6.4 (10F569)
      Kernel Version: Darwin 10.4.0
      Boot Volume: Macintosh HD
      Boot Mode: Normal

R version 2.12.0 (2010-10-15)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

The error is the same on 32-bit...

Thanks for your help in advance!
Ralf