Gramps gives strange errors after new install or upgrade
Many problems reported with Gramps turn out to be the consequence of installing a new version of Gramps "on top" of an older installed version (this is particularly important when installing from source). Such an install can lead to problems both in Windows and Linux. If you have done that and are experiencing problems, it might help uninstalling and installing again.
Gramps only properly generates .gv output format on GraphViz based reports
You have GraphViz package installed but you cannot use all available output formats for Gramps' reports based on GraphViz, because generated files are missing or not very nice. Using the last available GraphViz package for your distribution may often fix some issues. Also, PDF (GraphViz) or PostScript issues could be related to your cairo library (or python-cairo).