Fix bug reported by Dieter Menne, plus new errors introduced in r1137

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgl/pkg/rgl@1142 79a1b648-8b68-254f-b20b-c0b50f5137bf
Corrected bug fix for Dieter Menne's bug.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgl/pkg/rgl@1143 79a1b648-8b68-254f-b20b-c0b50f5137bf