Very strange! What if you try to recompile R from source, and add the --with-cairo option (or whatever the syntax is)? Before you make and make install, you should see whether the cairo capability is set up appropriately (it prints right at the end of the configure command).
We have directions (for RHEL) at:
And for a few different architectures at: http://docs.rstudio.com/connect/admin/getting-started.html#r-source