When I want change my project and I select setting and the project properties . It's will give me some message, like "Exception - Bad allocation" How do fix the problem ?
This sounds like a bug, so you'll probably want to report it to the QGIS bug tracker which you can find here: http://hub.qgis.org/projects/quantum-gis/issues
If it is a bug they'll be able to fix it for everyone. Be sure to provide as much information as you can. There are some good generic "how do I report a bug" web-pages around: