When you add project and type in a name, it won't recognize the name without the accents or diacritical marks.
For example, I created this project http://www.geni.com/projects/Jewish-families-from-Hermanuv-Mestec-Bohemia-Czech-Republic/15155
If I go to a profile and try to add to the project by typing Herman. . . the project doesn't show up because the project name is Heřmanův Městec.
The search feature on the drop-down Find a Project box when you add projects should recognize the equivalent accent-free characters.