class name clashes with same package name [urgent]

I start using IDEA recently. After creating project successfully, when i compile my class it gives me the error message "GUIListener clashes with package of same name" (GUIListener is the name of my class). I am not using any package, then why it gives such error!!! when i compile the same file thru command line, it was a success. It is something happened with IDEA, i guess. My classes are in a directory having same name as my class (GUIListener), but there is no package statement in my java file. plz any expert suggestions??

Raheel.