[R] package ca/rgl for ubuntu?

[Manderscheid Katharina]

hi,
for some unknown reason i cannot install the package ca in R running in a ubuntu mint system. i keep getting the following error message:

configure: error: missing required header GL/gl.h
ERROR: configuration failed for package ‘rgl’
* removing ‘/home/kat/R/i486-pc-linux-gnu-library/2.12/rgl’
ERROR: dependency ‘rgl’ is not available for package ‘ca’
* removing ‘/home/kat/R/i486-pc-linux-gnu-library/2.12/ca’

Die heruntergeladenen Pakete sind in 
	‘/tmp/Rtmp7r6s3h/downloaded_packages’
Warnmeldungen:
1: In install.packages("ca") :
  Installation des Pakets 'rgl' hatte Exit-Status ungleich 0
2: In install.packages("ca") :
  Installation des Pakets 'ca' hatte Exit-Status ungleich 0

thanks a lot for your help!
katharina