Bugfixes according to error messages from CRAN

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pcalg@242 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merged trunk to dev branch

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pcalg@243 edb9625f-4e0d-4859-8d74-9fd3b1da38cb