R stops abruptly applying textures in rgl

Hi,
When applying textures to an rgl object I can do it without problem if the applied texture if the texture file is called in an expand form [1]. However if the same file is called with tilde [2], R will stop abruptly. I've tested it in three different machines, all running 9.2. The same in Unbuntu 13.04 drops a warning message [3] but R continues running.
Agustin
[1] /Users/myuser/myfile.png
[2] ~/myfile.png
[3] In rgl.material(...) :
   RGL: Pixmap load: unable to open file '~/gvSIG-desktop/gvSIG-desktop-2066/theme/splash.png' for reading