cann't connected to X server

用qCreater 编译完的程序，不能执行。

报这个错误时解决办法。。

The general causes for this are as follows:

1. DISPLAY not set in the environment.
   Solution:

   export DISPLAY=:0.0 ./myQtCmdHere 

   ( This one doesn't appear to be the one at fault though, as its saying which X display its trying to connect to. Also, its not always 0.0, but most of the time it is )

2. Non-Authorised User trying to run the X Application
   Solution ( as X owning user, ie: yourself )